485BPOS

As filed with the Securities and Exchange Commission on November 7, 2012

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-1A

File Nos. 2-75152, 811-03343

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933	x
Pre-Effective Amendment No.	¨
Post-Effective Amendment No. 43	¨

and/or

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940	x
Amendment No. 46	¨

SIT LARGE CAP GROWTH FUND, INC.

(Exact Name of Registrant as Specified in Charter)

File Nos. 2-75151, 811-03342

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933	x
Pre-Effective Amendment No.	¨
Post-Effective Amendment No. 43	¨

and/or

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940	x
Amendment No. 46	¨

SIT MID CAP GROWTH FUND, INC.

(Exact Name of Registrant as Specified in Charter)

File Nos. 33-42101, 811-06373

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933	x
Pre-Effective Amendment No.	¨
Post-Effective Amendment No. 42	¨

and/or

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940	x
Amendment No. 43	¨

SIT MUTUAL FUNDS, INC.

(Exact Name of Registrant as Specified in Charter)

3300 IDS Center,

Minneapolis, Minnesota 55402

(Address of Principal Executive Offices) (Zip Code)

(612) 332-3223

(Registrants’ Telephone Number, including Area Code)

Kelly K. Boston, Esq.

Sit Mutual Funds

3300 IDS Center

Minneapolis, Minnesota 55402

(Name and Address of Agent for Service)

Copy to:

Michael J. Radmer, Esq.

Dorsey & Whitney, LLP

50 South 6^th Street, Suite 1500

Minneapolis, Minnesota 55402

It is proposed that this filing will become effective (check appropriate box):

x immediately upon filing pursuant to paragraph (b) of rule 485

¨ on (specify date) pursuant to paragraph (b) of rule 485

¨ 60 days after filing pursuant to paragraph (a)(1) of rule 485

¨ on (specify date) pursuant to paragraph (a)(1) of rule 485

¨ 75 days after filing pursuant to paragraph (a)(2) of rule 485

¨ on (specify date) pursuant to paragraph (a)(2) of rule 485

If appropriate, check the following box:

¨ This post-effective amendment designates a new effective date for a previously filed post effective amendment.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant has duly caused this Registration Statement on Form N-1A to be signed on its behalf by the undersigned, thereunder duly authorized, in the City of Minneapolis, State of Minnesota, on the 7th day of November 2012.

SIT LARGE CAP GROWTH FUND, INC. (Registrant)
By	/s/ Roger J. Sit
	Roger J. Sit, Chairman

Pursuant to the requirements of the Securities Act of 1933, this Post-Effective Amendment to the Registrant’s Registration Statement has been signed below by the following persons in the capacities and on the dates indicated. The enclosed Amendment does not contain disclosures that would render it ineligible to become effective pursuant to Rule 485(b).

Signature and Title
/s/ Roger J. Sit Roger J. Sit, Chairman (Principal Executive Officer)	Dated: November 7, 2012
/s/ Paul E. Rasmussen Paul E. Rasmussen, Treasurer (Principal Financial Officer and Accounting Officer)	Dated: November 7, 2012
William E. Frenzel, Director*
Edward M. Giles, Director*
Sidney L. Jones, Director*
Bruce C. Lueck, Director*
Donald W. Phillips, Director*
Barry N. Winslow, Director*

By	/s/ Roger J. Sit	Dated: November 7, 2012
	Roger J. Sit, Attorney-in-fact

* Pursuant to a power of attorney filed previously with the Commission.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant has duly caused this Registration Statement on Form N-1A to be signed on its behalf by the undersigned, thereunder duly authorized, in the City of Minneapolis, State of Minnesota, on the 7th day of November 2012.

SIT MID CAP GROWTH FUND, INC. (Registrant)
By	/s/ Roger J. Sit
	Roger J. Sit, Chairman

Pursuant to the requirements of the Securities Act of 1933, this Post-Effective Amendment to the Registrant’s Registration Statement has been signed below by the following persons in the capacities and on the dates indicated. The enclosed Amendment does not contain disclosures that would render it ineligible to become effective pursuant to Rule 485(b).

Signature and Title
/s/ Roger J. Sit Roger J. Sit, Chairman (Principal Executive Officer)	Dated: November 7, 2012
/s/ Paul E. Rasmussen Paul E. Rasmussen, Treasurer (Principal Financial Officer and Accounting Officer)	Dated: November 7, 2012
William E. Frenzel, Director*
Edward M. Giles, Director*
Sidney L. Jones, Director*
Bruce C. Lueck, Director*
Donald W. Phillips, Director*
Barry N. Winslow, Director*

By	/s/ Roger J. Sit	Dated: November 7, 2012
	Roger J. Sit, Attorney-in-fact

* Pursuant to a power of attorney filed previously with the Commission.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant has duly caused this Registration Statement on Form N-1A to be signed on its behalf by the undersigned, thereunder duly authorized, in the City of Minneapolis, State of Minnesota, on the 7th day of November 2012.

SIT MUTUAL FUNDS, INC. (Registrant)
By	/s/ Roger J. Sit
	Roger J. Sit, Chairman

Pursuant to the requirements of the Securities Act of 1933, this Post-Effective Amendment to the Registrant’s Registration Statement has been signed below by the following persons in the capacities and on the dates indicated. The enclosed Amendment does not contain disclosures that would render it ineligible to become effective pursuant to Rule 485(b).

Signature and Title
/s/ Roger J. Sit Roger J. Sit, Chairman (Principal Executive Officer)	Dated: November 7, 2012
/s/ Paul E. Rasmussen Paul E. Rasmussen, Treasurer (Principal Financial Officer and Accounting Officer)	Dated: November 7, 2012
William E. Frenzel, Director*
Edward M. Giles, Director*
Sidney L. Jones, Director*
Bruce C. Lueck, Director*
Donald W. Phillips, Director*
Barry N. Winslow, Director*

By	/s/ Roger J. Sit	Dated: November 7, 2012
	Roger J. Sit, Attorney-in-fact

* Pursuant to a power of attorney filed previously with the Commission.

EXHIBIT INDEX

Index No.	Description of Exhibit
EX-101.INS	XBRL Instance Document
EX-101.SCH	XBRL Taxonomy Extension Schema Document
EX-1-1.CAL	XBRL Taxonomy Extension Calculation Linkbase
EX-101.DEF	XBRL Taxonomy Extension Definition Linkbase
EX-101.LAB	XBRL Taxonomy Extension Labels Linkbase
EX-101.PRE	XBRL Taxonomy Extension Presentation Linkbase

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SIT MUTUAL FUNDS INC
Prospectus Date	rr_ProspectusDate	Nov. 01, 2012
Sit Developing Markets Growth Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	SUMMARY INFORMATION SIT DEVELOPING MARKETS GROWTH FUND
Objective [Heading]	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks to maximize long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	FEES AND EXPENSES OF THE FUND
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	PORTFOLIO TURNOVER
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transactions costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 22.56% of the average value of the portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	22.56%
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	The total annual fund operating expenses do not correlate to the ratio of expenses to average net assets shown in the Fund’s Financial Highlights, which does not include Acquired Fund Fees and Expenses.
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year, that the Fund’s operating expenses remain the same, and that you redeem all of your shares at the end of those periods. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	PRINCIPAL INVESTMENT STRATEGIES
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its objective by investing, under normal market conditions, at least 80% of its net assets in common stocks of companies domiciled or operating in a developing market. Developing markets are those countries that: have emerging stock markets as defined by the International Finance Corporation, have low-to middle-income economies according to the World Bank, or have similar developing characteristics, for example, countries in the MSCI EM Index and Hong Kong are considered to be developing. As of September 30, 2012, the Fund held investments in Hong Kong, Philippines, South Korea, Taiwan, Thailand, Brazil, Mexico, South Africa, Australia, China, Singapore, Israel, Russia, India, Indonesia, Peru, Chile, Argentina, and Sweden. The Fund also held investments in companies domiciled in Great Britain, which have substantial business activities in developing markets. In selecting investments for the Fund, the Adviser begins by selecting countries or regions in which to invest. In making its selections, the Adviser considers several factors affecting the economy and equity market of foreign countries and regions, including: economic trends, earnings outlook, liquidity within the market, fiscal and monetary policy, currency exchange rate expectations, investment valuation, market sentiment, and social and political trends. After the country and regional allocations are determined, the Adviser seeks industries and sectors that appear to have strong earnings growth prospects. Within the selected industries and sectors, the Adviser invests in foreign growth-oriented companies it believes exhibit the potential for superior growth. The Adviser believes that a company’s earnings growth is the primary determinant of its potential long-term return and evaluates a company’s potential for above average long-term earnings and revenue growth. Several factors are considered in the Adviser’s evaluation of a company, including: unique product or service, growing product demand, regional or country dominance and growing market share, management experience and capabilities, and strong financial condition. When selling equity securities for the Fund, the Adviser considers several factors, including changes in a company’s fundamentals and anticipated earnings. The Fund invests in small, medium and large sized companies. Small companies generally have capitalizations of under $3.0 billion, and large companies generally have a capitalization greater than $5 billion. The Fund may invest in securities representing underlying international securities such as sponsored American Depository Receipts, European Depository Receipts and Global Depository Receipts. In order to hedge against adverse movements in currency exchange rates, the Fund may from time to time enter into forward foreign currency exchange contracts.
Risk [Heading]	rr_RiskHeading	PRINCIPAL INVESTMENT RISKS
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	Developing Markets Risk: Investment in developing markets are subject to unique political, economic, and market risks that can cause the Fund’s investments to be more volatile and less liquid than investments in developed markets. Foreign Currency Hedging Transactions Risk: If the Adviser’s forecast of exchange rate movements is incorrect, the Fund may realize losses on their foreign currency transactions. In addition, the Fund’s hedging transactions may prevent the Funds from realizing the benefits of a favorable change in the value of foreign currencies. Growth Style Investing Risk: Different types of stocks tend to shift into and out of favor with stock market investors depending on market and economic conditions. The Fund invests in growth style stocks. The Fund’s performance may at times be better or worse than the performance of funds that focus on other types of stocks or that have a broader investment style. International Investing Risk: International investing involves risks not typically associated with investing in U.S. securities which may adversely affect the Fund’s investment. These risks include currency risk, foreign securities market risk, foreign tax risk, information risk, investment restriction risk, and political and economic risks. Management Risk: A strategy used by the investment management team may not produce the intended results. Market Risk: The market value of securities may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, or the market as a whole. The market value of securities may fluctuate, sometimes rapidly and unpredictably. Mid Cap Stock Risk: Stocks of mid cap stocks may be subject to more abrupt or erratic market movements than stocks of larger, more established companies. Small Cap Stock Risk: Stocks of smaller companies involve substantial risk. Prices of small cap stocks may be subject to more abrupt or erratic market movements than stocks of larger, more established companies. Additionally, for certain small cap stocks, there may also be limited liquidity, or trading opportunities at a favorable price or time.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	HISTORICAL PERFORMANCE
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide information on the Fund’s volatility and performance. The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future. The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance. Updated performance information is available at the Fund’s website at www.sitfunds.com or by calling 800-332-5580. After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	800-332-5580
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.sitfunds.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Annual Total Returns for calendar years ended December 31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The Fund’s year-to-date return as of 9/30/12 (not annualized) was 5.29%. Best Quarter: 32.98% (2Q09) Worst Quarter: -30.73% (4Q08)
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns for periods ended December 31, 2011
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Sit Developing Markets Growth Fund | Sit Developing Markets Growth Fund
Risk/Return:	rr_RiskReturnAbstract
Redemption Fee (as a percentage of amount redeemed only on shares held for less than 30 days)	rr_RedemptionFeeOverRedemption	2.00%
Management Fees	rr_ManagementFeesOverAssets	2.00%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	2.01%	[1]
1 Year	rr_ExpenseExampleYear01	206
3 Years	rr_ExpenseExampleYear03	636
5 Years	rr_ExpenseExampleYear05	1,093
10 Years	rr_ExpenseExampleYear10	2,355
2002	rr_AnnualReturn2002	(18.37%)
2003	rr_AnnualReturn2003	45.96%
2004	rr_AnnualReturn2004	16.54%
2005	rr_AnnualReturn2005	33.77%
2006	rr_AnnualReturn2006	31.59%
2007	rr_AnnualReturn2007	40.72%
2008	rr_AnnualReturn2008	(55.26%)
2009	rr_AnnualReturn2009	73.97%
2010	rr_AnnualReturn2010	14.53%
2011	rr_AnnualReturn2011	(18.48%)
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2012
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	5.29%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	32.98%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(30.73%)
1 Year	rr_AverageAnnualReturnYear01	(18.48%)
5 Years	rr_AverageAnnualReturnYear05	0.45%
10 Years	rr_AverageAnnualReturnYear10	9.59%
Sit Developing Markets Growth Fund | Return after taxes on distributions | Sit Developing Markets Growth Fund
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(19.58%)
5 Years	rr_AverageAnnualReturnYear05	(0.14%)
10 Years	rr_AverageAnnualReturnYear10	9.25%
Sit Developing Markets Growth Fund | Return after taxes on distributions and sale of Fund shares | Sit Developing Markets Growth Fund
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(10.58%)
5 Years	rr_AverageAnnualReturnYear05	0.34%
10 Years	rr_AverageAnnualReturnYear10	8.53%
Sit Developing Markets Growth Fund | MSCI Emerging Markets Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(20.41%)
5 Years	rr_AverageAnnualReturnYear05	0.08%
10 Years	rr_AverageAnnualReturnYear10	11.19%

[1] The total annual fund operating expenses do not correlate to the ratio of expenses to average net assets shown in the Fund's Financial Highlights, which does not include Acquired Fund Fees and Expenses.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SIT MUTUAL FUNDS INC
Prospectus Date	rr_ProspectusDate	Nov. 01, 2012
Sit Small Cap Growth Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	SUMMARY INFORMATION SIT SMALL CAP GROWTH FUND
Objective [Heading]	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks to maximize long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	FEES AND EXPENSES OF THE FUND
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	PORTFOLIO TURNOVER
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transactions costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 22.32% of the average value of the portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	22.32%
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year, that the Fund’s operating expenses remain the same, and that you redeem all of your shares at the end of those periods. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	PRINCIPAL INVESTMENT STRATEGIES
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its objective by investing, under normal market conditions, at least 80% of its net assets in common stocks of companies with capitalizations at the time of purchase of up to $3.0 billion, or up to the market capitalization of the largest company included in the Russell 2000 Index measured at the end of the previous twelve months. The Russell 2000 Index measures the performance of the 2,000 smallest companies in the Russell 3000 Index (which is made up of the 3,000 largest U.S. companies based on total market capitalization). As of September 30, 2012, the market capitalization of the largest company included in the Russell 2000 Index measured at the end of the previous twelve months was $4.6 billion. The Adviser invests in domestic growth-oriented small companies it believes exhibit the potential for superior growth. The Adviser believes that a company’s earnings growth is the primary determinant of its potential long-term return and evaluates a company’s potential for above average long-term earnings and revenue growth. Several factors are considered in the Adviser’s evaluation of a company, including: unique product or service, growing product demand, dominant and growing market share, management experience and capabilities, and strong financial condition. When selling equity securities for the Fund, the Adviser considers several factors, including changes in a company’s fundamentals and anticipated earnings.
Risk [Heading]	rr_RiskHeading	PRINCIPAL INVESTMENT RISKS
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	You could lose money by investing in the Fund. The principal risks of investing in the Fund are as follows: Growth Style Investing Risk: Different types of stocks tend to shift into and out of favor with stock market investors depending on market and economic conditions. The Fund invests in growth style stocks. The Fund’s performance may at times be better or worse than the performance of funds that focus on other types of stocks or that have a broader investment style. Management Risk: A strategy used by the investment management team may not produce the intended results. Market Risk: The market value of securities may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, or the market as a whole. The market value of securities may fluctuate, sometimes rapidly and unpredictably. Small Cap Stock Risk: Stocks of smaller companies involve substantial risk. Prices of small cap stocks may be subject to more abrupt or erratic market movements than stocks of larger, more established companies. Addionally, for certain small cap stocks, there may also be limited liquidity, or trading opportunities at a favorable price or time.
Risk Lose Money [Text]	rr_RiskLoseMoney	You could lose money by investing in the Fund.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	HISTORICAL PERFORMANCE
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide information on the Fund’s volatility and performance. The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future. The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance. Updated performance information is available at the Fund’s website at www.sitfunds.com or by calling 800-332-5580. After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	800-332-5580
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.sitfunds.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Annual Total Returns for calendar years ended December 31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The Fund’s year-to-date return as of 9/30/12 (not annualized) was 12.87%. Best Quarter: 20.02% (2Q03) Worst Quarter: -26.22% (4Q08)
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns for periods ended December 31, 2011
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Sit Small Cap Growth Fund | Sit Small Cap Growth Fund
Risk/Return:	rr_RiskReturnAbstract
Redemption Fee (as a percentage of amount redeemed only on shares held for less than 30 days)	rr_RedemptionFeeOverRedemption	2.00%
Management Fees	rr_ManagementFeesOverAssets	1.50%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.50%
1 Year	rr_ExpenseExampleYear01	154
3 Years	rr_ExpenseExampleYear03	477
5 Years	rr_ExpenseExampleYear05	824
10 Years	rr_ExpenseExampleYear10	1,801
2002	rr_AnnualReturn2002	(26.22%)
2003	rr_AnnualReturn2003	34.57%
2004	rr_AnnualReturn2004	6.79%
2005	rr_AnnualReturn2005	18.52%
2006	rr_AnnualReturn2006	7.99%
2007	rr_AnnualReturn2007	20.43%
2008	rr_AnnualReturn2008	(42.96%)
2009	rr_AnnualReturn2009	33.06%
2010	rr_AnnualReturn2010	27.28%
2011	rr_AnnualReturn2011	(0.23%)
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2012
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	12.87%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2003
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	20.02%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(26.22%)
1 Year	rr_AverageAnnualReturnYear01	(0.23%)
5 Years	rr_AverageAnnualReturnYear05	3.03%
10 Years	rr_AverageAnnualReturnYear10	4.65%
Sit Small Cap Growth Fund | Return after taxes on distributions | Sit Small Cap Growth Fund
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(0.23%)
5 Years	rr_AverageAnnualReturnYear05	3.03%
10 Years	rr_AverageAnnualReturnYear10	4.65%
Sit Small Cap Growth Fund | Return after taxes on distributions and sale of Fund shares | Sit Small Cap Growth Fund
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(0.15%)
5 Years	rr_AverageAnnualReturnYear05	2.59%
10 Years	rr_AverageAnnualReturnYear10	4.06%
Sit Small Cap Growth Fund | Russell 2000 Growth Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(2.91%)
5 Years	rr_AverageAnnualReturnYear05	2.09%
10 Years	rr_AverageAnnualReturnYear10	4.48%

XML

Sit International Growth Fund

SUMMARY INFORMATION
SIT INTERNATIONAL GROWTH FUND

INVESTMENT OBJECTIVE

The Fund seeks long-term growth.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees	Sit International Growth Fund
Redemption Fee (as a percentage of amount redeemed only on shares held for less than 30 days)	2.00%

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses	Sit International Growth Fund
Management Fees	1.50%
Total Annual Fund Operating Expenses	1.50%

Example

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year, that the Fund’s operating expenses remain the same, and that you redeem all of your shares at the end of those periods. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:

Expense Example (USD $)	1 Year	3 Years	5 Years	10 Years
Sit International Growth Fund	154	477	824	1,801

PORTFOLIO TURNOVER

The Fund pays transactions costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 27.82% of the average value of the portfolio.

PRINCIPAL INVESTMENT STRATEGIES

The Fund seeks to achieve its objective by investing, under normal market conditions, at least 90% of its net assets in common stocks of companies domiciled outside the United States.

In selecting investments for the Fund, the Adviser begins by selecting countries or regions in which to invest. In making its selections, the Adviser considers several factors affecting the economy and equity market of foreign countries and regions, including:

• economic trends,

• earnings outlook,

• liquidity within the market,

• fiscal and monetary policy,

• currency exchange rate expectations,

• market sentiment, and

• social and political trends.

After the country and regional allocations are determined, the Adviser seeks industries and sectors that it believes have earnings growth prospects that are greater than the average. Within the selected industries and sectors, the Adviser invests in foreign growth-oriented companies it believes exhibit the potential for superior growth. The Adviser believes that a company’s earnings growth is the primary determinant of its potential long-term return and evaluates a company's potential for above average long-term earnings and revenue growth.

Several factors are considered in the Adviser’s evaluation of a company, including:

• unique product or service,

• growing product demand,

• dominant and growing market share,

• management experience and capabilities, and

• strong financial condition.

When selling equity securities for the Fund, the Adviser considers several factors, including changes in a company's fundamentals and anticipated earnings.

The Fund invests in common stocks of issuers domiciled in at least three foreign countries. As of September 30, 2012, the Fund was invested in common stocks of companies domiciled in 23 foreign countries. Up to 50% of the Fund's total assets may be invested in equity securities of small-to medium-sized emerging growth companies in developed markets (such as Germany and Japan) and developing markets (such as Thailand and Brazil). Small companies generally have a capitalization of under $3.0 billion, and medium-sized companies generally have capitalizations between $2 and $15 billion. Emerging growth companies are small-and medium-sized companies that the Adviser believes have a potential for earnings growth over time that is above the growth rate of more established companies or are early in their life cycles.

The Fund may invest in securities representing underlying international securities such as sponsored American Depository Receipts, European Depository Receipts and Global Depository Receipts.

In order to hedge against adverse movements in currency exchange rates, the Fund may from time to time enter into forward foreign currency exchange contracts.

PRINCIPAL INVESTMENT RISKS

• Developing Markets Risk: Investment in developing markets are subject to unique political, economic, and market risks that can cause the Fund's investments to be more volatile and less liquid than investments in developed markets.

• Foreign Currency Hedging Transactions Risk: If the Adviser's forecast of exchange rate movements is incorrect, the Fund may realize losses on their foreign currency transactions. In addition, the Fund's hedging transactions may prevent the Funds from realizing the benefits of a favorable change in the value of foreign currencies.

• Growth Style Investing Risk: Different types of stocks tend to shift into and out of favor with stock market investors depending on market and economic conditions. The Fund invests in growth style stocks. The Fund's performance may at times be better or worse than the performance of funds that focus on other types of stocks or that have a broader investment style.

• International Investing Risk: International investing involves risks not typically associated with investing in U.S. securities which may adversely affect the Fund's investment. These risks include currency risk, foreign securities market risk, foreign tax risk, information risk, investment restriction risk, and political and economic risks.

• Management Risk: A strategy used by the investment management team may not produce the intended results.

• Market Risk: The market value of securities may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, or the market as a whole. The market value of securities may fluctuate, sometimes rapidly and unpredictably.

• Mid Cap Stock Risk: Stocks of mid cap stocks may be subject to more abrupt or erratic market movements than stocks of larger, more established companies.

• Small Cap Stock Risk: Stocks of smaller companies involve substantial risk. Prices of small cap stocks may be subject to more abrupt or erratic market movements than stocks of larger, more established companies. Additionally, for certain small cap stocks, there may also be limited liquidity, or trading opportunities at a favorable price or time.

HISTORICAL PERFORMANCE

The following bar chart and table provide information on the Fund’s volatility and performance. The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future. The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance. Updated performance information is available at the Fund’s website at www.sitfunds.com or by calling 800-332-5580.

After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

Annual Total Returns for calendar years ended December 31

The Fund’s year-to-date return as of 9/30/12 (not annualized) was 11.28%.
Best Quarter: 23.58% (2Q09)
Worst Quarter: -23.52% (4Q08)

Average Annual Total Returns for periods ended December 31, 2010

Average Annual Total Returns	1 Year	5 Years	10 Years
Sit International Growth Fund	(10.80%)	(4.46%)	0.96%
Sit International Growth Fund Return after taxes on distributions	(11.05%)	(4.64%)	0.83%
Sit International Growth Fund Return after taxes on distributions and sale of Fund shares	(6.71%)	(3.73%)	0.82%
Sit International Growth Fund MSCI EAFE Growth Index (reflects no deduction for fees, expenses or taxes)	(12.11%)	(3.16%)	4.27%

XML

Sit Dividend Growth Fund

SUMMARY INFORMATION
SIT DIVIDEND GROWTH FUND

INVESTMENT OBJECTIVE

The Fund primarily seeks to provide current income that exceeds the dividend yield of the S&P 500 Index and that grows over a period of years.

Secondarily the Fund seeks long-term capital appreciation.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees Sit Dividend Growth Fund	Class I	Class S
Redemption Fee (as a percentage of amount redeemed only on shares held for less than 30 days)	2.00%	2.00%

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses Sit Dividend Growth Fund		Class I	Class S
Management Fees		1.00%	1.00%
Distribution (12b-1) fees		none	0.25%
Acquired Fund Fees and Expenses	[1]	0.15%	0.15%
Total Annual Fund Operating Expenses	[1]	1.15%	1.40%

Example

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year, that the Fund’s operating expenses remain the same, and that you redeem all of your shares at the end of those periods. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:

Expense Example Sit Dividend Growth Fund (USD $)	1 Year	3 Years	5 Years	10 Years
Class I	118	367	636	1,404
Class S	144	446	771	1,689

PORTFOLIO TURNOVER

The Fund pays transactions costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 26.84% (both classes) of the average value of the portfolio.

PRINCIPAL INVESTMENT STRATEGIES

The Fund seeks to achieve its objectives by investing, under normal market conditions, at least 80% of its net assets in dividend-paying common stocks. The Fund may invest the balance of its assets in preferred stocks, convertible bonds, and U.S. Treasury securities.

The Adviser invests in dividend paying growth-oriented companies it believes exhibit the potential for growth and growing dividend payments. The Adviser believes that a company’s earnings growth is a primary determinant of its potential long-term return, and that a record of increasing dividend payments is a strong indicator of financial health and growth prospects. By investing in dividend paying stocks it is anticipated that the holdings will tend to be in large to medium-sized companies (companies with market capitalizations in excess of $2 billion). The Adviser considers several factors in its evaluation of a company’s potential for above average long-term earnings, revenue, and dividend growth, including:

• a record of paying dividends,

• strong prospects for growing dividend payments indicated in part by growing earnings and cash flow,

• unique product or service,

• growing product demand,

• dominant and growing market share,

• management experience and capabilities, and

• strong financial condition.

Since stocks that pay dividends tend to be less volatile and may not experience the same capital appreciation as stocks that don’t pay dividends, the Fund’s diversified portfolio of dividend paying stocks is expected to have lower volatility than that of the S&P 500 Index, but with a higher dividend yield and greater prospects for dividend growth.

The Fund may invest up to 20% of its net assets in securities of issuers domiciled outside the U.S.

When selling equity securities for the Fund, the Adviser considers several factors, including changes in a company’s fundamentals, anticipated earnings, anticipated dividend payments and financial position.

PRINCIPAL INVESTMENT RISKS

You could lose money by investing in the Fund. The principal risks of investing in the Fund are as follows:

• Dividend Paying Company Risk: The Fund’s income objective may limit its ability to appreciate during a broad market advance because dividend paying stocks may not experience the same capital appreciation as non-dividend paying stocks. In addition, stocks held by the Fund may reduce or stop paying dividends which could affect the Fund’s ability to generate income.

• Growth Style Investing Risk: Different types of stocks tend to shift into and out of favor with stock market investors depending on market and economic conditions. The Fund invests in growth style stocks. The Fund’s performance may at times be better or worse than the performance of funds that focus on other types of stocks or that have a broader investment style.

• International Investing Risk: Because the Fund may invest in foreign securities, there is an international investing risk. International investing involves risks not typically associated with investing in U.S. securities which may adversely affect the Fund’s investment. These risks include currency risk, foreign securities market risk, foreign tax risk, information risk, investment restriction risk, and political and economic risks.

• Management Risk: A strategy used by the investment management team may not produce the intended results.

• Market Risk: The market value of securities may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, or the market as a whole. The market value of securities may fluctuate, sometimes rapidly and unpredictably.

• Mid Cap Stock Risk: Stocks of mid cap stocks may be subject to more abrupt or erratic market movement than stocks of larger, more established companies.

HISTORICAL PERFORMANCE

The following bar chart and table provide information on the Fund’s volatility and performance. The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future. The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for Class I shares. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance. Updated performance information is available at the Fund’s website at www.sitfunds.com or by calling 800-332-5580.

After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown only for Class I shares; after-tax returns for Class S shares will vary.

Annual Total Returns for calendar years ended December 31 (Class I)

The Fund’s year-to-date return as of 9/30/12 (not annualized) was 13.62%.
Best Quarter: 14.44% (2Q09)
Worst Quarter: -19.13% (4Q08)

Average Annual Total Returns for periods ended December 31, 2011

Average Annual Total Returns Sit Dividend Growth Fund	1 Year	5 Years	Life of Fund	Inception Date
Class I	3.29%	3.72%	7.03%	Dec. 31, 2003
Class I Return after taxes on distributions	2.95%	3.11%	6.48%
Class I Return after taxes on distributions and sale of Fund shares	2.59%	3.07%	6.04%
Class S	2.98%	3.45%	4.91%	Mar. 31, 2006
S&P 500 Index (reflects no deduction for fees, expenses or taxes)	2.11%	(0.25%)	3.63%

[1] The total annual fund operating expenses do not correlate to the ratio of expenses to average net assets shown in the Fund's Financial Highlights, which does not include Acquired Fund Fees and Expenses.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SIT MUTUAL FUNDS INC
Prospectus Date	rr_ProspectusDate	Nov. 01, 2012
Sit International Growth Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	SUMMARY INFORMATION SIT INTERNATIONAL GROWTH FUND
Objective [Heading]	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks long-term growth.
Expense [Heading]	rr_ExpenseHeading	FEES AND EXPENSES OF THE FUND
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	PORTFOLIO TURNOVER
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transactions costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 27.82% of the average value of the portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	27.82%
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year, that the Fund’s operating expenses remain the same, and that you redeem all of your shares at the end of those periods. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	PRINCIPAL INVESTMENT STRATEGIES
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its objective by investing, under normal market conditions, at least 90% of its net assets in common stocks of companies domiciled outside the United States. In selecting investments for the Fund, the Adviser begins by selecting countries or regions in which to invest. In making its selections, the Adviser considers several factors affecting the economy and equity market of foreign countries and regions, including: economic trends, earnings outlook, liquidity within the market, fiscal and monetary policy, currency exchange rate expectations, market sentiment, and social and political trends. After the country and regional allocations are determined, the Adviser seeks industries and sectors that it believes have earnings growth prospects that are greater than the average. Within the selected industries and sectors, the Adviser invests in foreign growth-oriented companies it believes exhibit the potential for superior growth. The Adviser believes that a company’s earnings growth is the primary determinant of its potential long-term return and evaluates a company's potential for above average long-term earnings and revenue growth. Several factors are considered in the Adviser’s evaluation of a company, including: unique product or service, growing product demand, dominant and growing market share, management experience and capabilities, and strong financial condition. When selling equity securities for the Fund, the Adviser considers several factors, including changes in a company's fundamentals and anticipated earnings. The Fund invests in common stocks of issuers domiciled in at least three foreign countries. As of September 30, 2012, the Fund was invested in common stocks of companies domiciled in 23 foreign countries. Up to 50% of the Fund's total assets may be invested in equity securities of small-to medium-sized emerging growth companies in developed markets (such as Germany and Japan) and developing markets (such as Thailand and Brazil). Small companies generally have a capitalization of under $3.0 billion, and medium-sized companies generally have capitalizations between $2 and $15 billion. Emerging growth companies are small-and medium-sized companies that the Adviser believes have a potential for earnings growth over time that is above the growth rate of more established companies or are early in their life cycles. The Fund may invest in securities representing underlying international securities such as sponsored American Depository Receipts, European Depository Receipts and Global Depository Receipts. In order to hedge against adverse movements in currency exchange rates, the Fund may from time to time enter into forward foreign currency exchange contracts.
Risk [Heading]	rr_RiskHeading	PRINCIPAL INVESTMENT RISKS
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	Developing Markets Risk: Investment in developing markets are subject to unique political, economic, and market risks that can cause the Fund's investments to be more volatile and less liquid than investments in developed markets. Foreign Currency Hedging Transactions Risk: If the Adviser's forecast of exchange rate movements is incorrect, the Fund may realize losses on their foreign currency transactions. In addition, the Fund's hedging transactions may prevent the Funds from realizing the benefits of a favorable change in the value of foreign currencies. Growth Style Investing Risk: Different types of stocks tend to shift into and out of favor with stock market investors depending on market and economic conditions. The Fund invests in growth style stocks. The Fund's performance may at times be better or worse than the performance of funds that focus on other types of stocks or that have a broader investment style. International Investing Risk: International investing involves risks not typically associated with investing in U.S. securities which may adversely affect the Fund's investment. These risks include currency risk, foreign securities market risk, foreign tax risk, information risk, investment restriction risk, and political and economic risks. Management Risk: A strategy used by the investment management team may not produce the intended results. Market Risk: The market value of securities may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, or the market as a whole. The market value of securities may fluctuate, sometimes rapidly and unpredictably. Mid Cap Stock Risk: Stocks of mid cap stocks may be subject to more abrupt or erratic market movements than stocks of larger, more established companies. Small Cap Stock Risk: Stocks of smaller companies involve substantial risk. Prices of small cap stocks may be subject to more abrupt or erratic market movements than stocks of larger, more established companies. Additionally, for certain small cap stocks, there may also be limited liquidity, or trading opportunities at a favorable price or time.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	HISTORICAL PERFORMANCE
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide information on the Fund’s volatility and performance. The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future. The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance. Updated performance information is available at the Fund’s website at www.sitfunds.com or by calling 800-332-5580. After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	800-332-5580
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.sitfunds.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Annual Total Returns for calendar years ended December 31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The Fund’s year-to-date return as of 9/30/12 (not annualized) was 11.28%. Best Quarter: 23.58% (2Q09) Worst Quarter: -23.52% (4Q08)
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns for periods ended December 31, 2010
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Sit International Growth Fund | Sit International Growth Fund
Risk/Return:	rr_RiskReturnAbstract
Redemption Fee (as a percentage of amount redeemed only on shares held for less than 30 days)	rr_RedemptionFeeOverRedemption	(2.00%)
Management Fees	rr_ManagementFeesOverAssets	1.50%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.50%
1 Year	rr_ExpenseExampleYear01	154
3 Years	rr_ExpenseExampleYear03	477
5 Years	rr_ExpenseExampleYear05	824
10 Years	rr_ExpenseExampleYear10	1,801
2002	rr_AnnualReturn2002	(29.84%)
2003	rr_AnnualReturn2003	28.70%
2004	rr_AnnualReturn2004	12.97%
2005	rr_AnnualReturn2005	14.67%
2006	rr_AnnualReturn2006	18.19%
2007	rr_AnnualReturn2007	16.08%
2008	rr_AnnualReturn2008	(44.99%)
2009	rr_AnnualReturn2009	27.65%
2010	rr_AnnualReturn2010	9.51%
2011	rr_AnnualReturn2011	(10.80%)
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2012
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	11.28%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	23.58%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(23.52%)
1 Year	rr_AverageAnnualReturnYear01	(10.80%)
5 Years	rr_AverageAnnualReturnYear05	(4.46%)
10 Years	rr_AverageAnnualReturnYear10	0.96%
Sit International Growth Fund | Return after taxes on distributions | Sit International Growth Fund
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(11.05%)
5 Years	rr_AverageAnnualReturnYear05	(4.64%)
10 Years	rr_AverageAnnualReturnYear10	0.83%
Sit International Growth Fund | Return after taxes on distributions and sale of Fund shares | Sit International Growth Fund
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(6.71%)
5 Years	rr_AverageAnnualReturnYear05	(3.73%)
10 Years	rr_AverageAnnualReturnYear10	0.82%
Sit International Growth Fund | MSCI EAFE Growth Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(12.11%)
5 Years	rr_AverageAnnualReturnYear05	(3.16%)
10 Years	rr_AverageAnnualReturnYear10	4.27%

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SIT MUTUAL FUNDS INC
Prospectus Date	rr_ProspectusDate	Nov. 01, 2012
SIT LARGE CAP GROWTH FUND INC | SIT LARGE CAP GROWTH FUND INC
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	SUMMARY INFORMATION SIT LARGE CAP GROWTH FUND
Objective [Heading]	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks to maximize long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	FEES AND EXPENSES OF THE FUND
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	PORTFOLIO TURNOVER
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transactions costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 15.06% of the average value of the portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	15.06%
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year, that the Fund’s operating expenses remain the same, and that you redeem all of your shares at the end of those periods. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	PRINCIPAL INVESTMENT STRATEGIES
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its objective by investing, under normal market conditions, at least 80% of its net assets in the common stocks of companies with capitalizations of $5 billion or more at the time of purchase. The Adviser invests in domestic growth-oriented companies it believes exhibit the potential for superior growth. The Fund focuses on stocks issued by companies with long records of earnings and revenue growth. The Adviser believes that a company’s earnings growth is the primary determinant of its potential long-term return and evaluates a company’s potential for above average long-term earnings and revenue growth. Several factors are considered in the Adviser’s evaluation of a company, including: unique product or service, growing product demand, dominant and growing market share, management experience and capabilities, and strong financial condition. When selling equity securities for the Fund, the Adviser considers several factors, including changes in a company’s fundamentals and anticipated earnings.
Risk [Heading]	rr_RiskHeading	PRINCIPAL INVESTMENT RISKS
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	You could lose money by investing in the Fund. The principal risks of investing in the Fund are as follows: Growth Style Investing Risk: Different types of stocks tend to shift into and out of favor with stock market investors depending on market and economic conditions. The Fund invests in growth style stocks. The Fund’s performance may at times be better or worse than the performance of funds that focus on other types of stocks or that have a broader investment style. Management Risk: A strategy used by the investment management team may not produce the intended results. Market Risk: The market value of securities may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, or the market as a whole. The market value of securities may fluctuate, sometimes rapidly and unpredictably.
Risk Lose Money [Text]	rr_RiskLoseMoney	You could lose money by investing in the Fund.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	HISTORICAL PERFORMANCE
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide information on the Fund’s volatility and performance. The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future. The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance. Updated performance information is available at the Fund’s website at www.sitfunds.com or by calling 800-332-5580. After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	800-332-5580
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.sitfunds.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Annual Total Returns for calendar years ended December 31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The Fund’s year-to-date return as of 9/30/12 (not annualized) was 15.92%. Best Quarter: 14.50% (2Q03) Worst Quarter: -21.13% (4Q08)
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns for periods ended December 31, 2011
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
SIT LARGE CAP GROWTH FUND INC | SIT LARGE CAP GROWTH FUND INC | SIT LARGE CAP GROWTH FUND INC
Risk/Return:	rr_RiskReturnAbstract
Redemption Fee (as a percentage of amount redeemed only on shares held for less than 30 days)	rr_RedemptionFeeOverRedemption	2.00%
Management Fees	rr_ManagementFeesOverAssets	1.00%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.00%
1 Year	rr_ExpenseExampleYear01	103
3 Years	rr_ExpenseExampleYear03	320
5 Years	rr_ExpenseExampleYear05	555
10 Years	rr_ExpenseExampleYear10	1,229
2002	rr_AnnualReturn2002	(30.58%)
2003	rr_AnnualReturn2003	26.34%
2004	rr_AnnualReturn2004	12.79%
2005	rr_AnnualReturn2005	9.59%
2006	rr_AnnualReturn2006	9.54%
2007	rr_AnnualReturn2007	14.14%
2008	rr_AnnualReturn2008	(34.10%)
2009	rr_AnnualReturn2009	28.14%
2010	rr_AnnualReturn2010	10.79%
2011	rr_AnnualReturn2011	(0.53%)
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2012
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	15.92%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2003
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	14.50%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(21.13%)
1 Year	rr_AverageAnnualReturnYear01	(0.53%)
5 Years	rr_AverageAnnualReturnYear05	1.22%
10 Years	rr_AverageAnnualReturnYear10	2.35%
SIT LARGE CAP GROWTH FUND INC | SIT LARGE CAP GROWTH FUND INC | Return after taxes on distributions | SIT LARGE CAP GROWTH FUND INC
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(0.64%)
5 Years	rr_AverageAnnualReturnYear05	1.13%
10 Years	rr_AverageAnnualReturnYear10	2.29%
SIT LARGE CAP GROWTH FUND INC | SIT LARGE CAP GROWTH FUND INC | Return after taxes on distributions and sale of Fund shares | SIT LARGE CAP GROWTH FUND INC
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(0.19%)
5 Years	rr_AverageAnnualReturnYear05	1.03%
10 Years	rr_AverageAnnualReturnYear10	2.02%
SIT LARGE CAP GROWTH FUND INC | SIT LARGE CAP GROWTH FUND INC | Russell 1000 Growth Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	2.64%
5 Years	rr_AverageAnnualReturnYear05	2.50%
10 Years	rr_AverageAnnualReturnYear10	2.60%

XML

Sit Small Cap Growth Fund

SUMMARY INFORMATION
SIT SMALL CAP GROWTH FUND

INVESTMENT OBJECTIVE

The Fund seeks to maximize long-term capital appreciation.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees	Sit Small Cap Growth Fund
Redemption Fee (as a percentage of amount redeemed only on shares held for less than 30 days)	2.00%

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses	Sit Small Cap Growth Fund
Management Fees	1.50%
Total Annual Fund Operating Expenses	1.50%

Example

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year, that the Fund’s operating expenses remain the same, and that you redeem all of your shares at the end of those periods. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:

Expense Example (USD $)	1 Year	3 Years	5 Years	10 Years
Sit Small Cap Growth Fund	154	477	824	1,801

PORTFOLIO TURNOVER

The Fund pays transactions costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 22.32% of the average value of the portfolio.

PRINCIPAL INVESTMENT STRATEGIES

The Fund seeks to achieve its objective by investing, under normal market conditions, at least 80% of its net assets in common stocks of companies with capitalizations at the time of purchase of up to $3.0 billion, or up to the market capitalization of the largest company included in the Russell 2000 Index measured at the end of the previous twelve months. The Russell 2000 Index measures the performance of the 2,000 smallest companies in the Russell 3000 Index (which is made up of the 3,000 largest U.S. companies based on total market capitalization). As of September 30, 2012, the market capitalization of the largest company included in the Russell 2000 Index measured at the end of the previous twelve months was $4.6 billion.

The Adviser invests in domestic growth-oriented small companies it believes exhibit the potential for superior growth. The Adviser believes that a company’s earnings growth is the primary determinant of its potential long-term return and evaluates a company’s potential for above average long-term earnings and revenue growth. Several factors are considered in the Adviser’s evaluation of a company, including:

• unique product or service,

• growing product demand,

• dominant and growing market share,

• management experience and capabilities, and

• strong financial condition.

When selling equity securities for the Fund, the Adviser considers several factors, including changes in a company’s fundamentals and anticipated earnings.

PRINCIPAL INVESTMENT RISKS

You could lose money by investing in the Fund. The principal risks of investing in the Fund are as follows:

• Growth Style Investing Risk: Different types of stocks tend to shift into and out of favor with stock market investors depending on market and economic conditions. The Fund invests in growth style stocks. The Fund’s performance may at times be better or worse than the performance of funds that focus on other types of stocks or that have a broader investment style.

• Management Risk: A strategy used by the investment management team may not produce the intended results.

• Market Risk: The market value of securities may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, or the market as a whole. The market value of securities may fluctuate, sometimes rapidly and unpredictably.

• Small Cap Stock Risk: Stocks of smaller companies involve substantial risk. Prices of small cap stocks may be subject to more abrupt or erratic market movements than stocks of larger, more established companies. Addionally, for certain small cap stocks, there may also be limited liquidity, or trading opportunities at a favorable price or time.

HISTORICAL PERFORMANCE

The following bar chart and table provide information on the Fund’s volatility and performance. The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future. The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance. Updated performance information is available at the Fund’s website at www.sitfunds.com or by calling 800-332-5580.

After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

Annual Total Returns for calendar years ended December 31

The Fund’s year-to-date return as of 9/30/12 (not annualized) was 12.87%.
Best Quarter: 20.02% (2Q03)
Worst Quarter: -26.22% (4Q08)

Average Annual Total Returns for periods ended December 31, 2011

Average Annual Total Returns	1 Year	5 Years	10 Years
Sit Small Cap Growth Fund	(0.23%)	3.03%	4.65%
Sit Small Cap Growth Fund Return after taxes on distributions	(0.23%)	3.03%	4.65%
Sit Small Cap Growth Fund Return after taxes on distributions and sale of Fund shares	(0.15%)	2.59%	4.06%
Sit Small Cap Growth Fund Russell 2000 Growth Index (reflects no deduction for fees, expenses or taxes)	(2.91%)	2.09%	4.48%

XML

SIT MID CAP GROWTH FUND INC | SIT MID CAP GROWTH FUND INC

SUMMARY INFORMATION
SIT MID CAP GROWTH FUND

INVESTMENT OBJECTIVE

The Fund seeks to maximize long-term capital appreciation.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees	SIT MID CAP GROWTH FUND INC
Redemption Fee (as a percentage of amount redeemed only on shares held for less than 30 days)	2.00%

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses	SIT MID CAP GROWTH FUND INC
Management Fees	1.25%
Total Annual Fund Operating Expenses	1.25%

Example

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year, that the Fund’s operating expenses remain the same, and that you redeem all of your shares at the end of those periods. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:

Expense Example (USD $)	1 Year	3 Years	5 Years	10 Years
SIT MID CAP GROWTH FUND INC	128	399	690	1,518

PORTFOLIO TURNOVER

The Fund pays transactions costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 16.23% of the average value of the portfolio.

PRINCIPAL INVESTMENT STRATEGIES

The Fund seeks to achieve its objective by investing, under normal market conditions, at least 80% of its net assets in the common stocks of companies with capitalizations of $2 billion to $15 billion at the time of purchase.

The Adviser invests in domestic growth-oriented medium to small companies it believes exhibit the potential for superior growth. The Adviser believes that a company’s earnings growth is the primary determinant of its potential long-term return and evaluates a company’s potential for above average long-term earnings and revenue growth. Several factors are considered in the Adviser’s evaluation of a company, including:

• unique product or service,

• growing product demand,

• dominant and growing market share,

• management experience and capabilities, and

• strong financial condition.

When selling equity securities for the Fund, the Adviser considers several factors, including changes in a company’s fundamentals and anticipated earnings.

PRINCIPAL INVESTMENT RISKS

You could lose money by investing in the Fund. The principal risks of investing in the Fund are as follows:

• Growth Style Investing Risk: Different types of stocks tend to shift into and out of favor with stock market investors depending on market and economic conditions. The Fund invests in growth style stocks. The Fund’s performance may at times be better or worse than the performance of funds that focus on other types of stocks or that have a broader investment style.

• Management Risk: A strategy used by the investment management team may not produce the intended results.

• Market Risk: The market value of securities may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, or the market as a whole. The market value of securities may fluctuate, sometimes rapidly and unpredictably.

• Mid Cap Stock Risk: Stocks of mid cap stocks may be subject to more abrupt or erratic market movements than stocks of larger, more established companies.

HISTORICAL PERFORMANCE

The following bar chart and table provide information on the Fund’s volatility and performance. The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future. The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance. Updated performance information is available at the Fund’s website at www.sitfunds.com or by calling 800-332-5580.

The table includes returns both before and after taxes. After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

Annual Total Returns for calendar years ended December 31

The Fund’s year-to-date return as of 9/30/12 (not annualized) was 15.47%.
Best Quarter: 19.71% (2Q09)
Worst Quarter: -26.99% (4Q08)

Average Annual Total Returns for periods ended December 31, 2011

Average Annual Total Returns	1 Year	5 Years	10 Years
SIT MID CAP GROWTH FUND INC	(6.53%)	0.91%	3.42%
SIT MID CAP GROWTH FUND INC Return after taxes on distributions	(6.53%)	0.79%	3.36%
SIT MID CAP GROWTH FUND INC Return after taxes on distributions and sale of Fund shares	(4.24%)	0.78%	2.97%
SIT MID CAP GROWTH FUND INC Russell Mid Cap Growth Index (reflects no deduction for fees, expenses or taxes)	(1.65%)	2.44%	5.29%

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SIT MUTUAL FUNDS INC
Prospectus Date	rr_ProspectusDate	Nov. 01, 2012
Sit Balanced Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	SUMMARY INFORMATION SIT BALANCED FUND
Objective [Heading]	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks long-term capital growth consistent with preservation of principal and seeks to provide shareholders with regular income.
Expense [Heading]	rr_ExpenseHeading	FEES AND EXPENSES OF THE FUND
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	PORTFOLIO TURNOVER
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transactions costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 47.01% of the average value of the portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	47.01%
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	The total annual fund operating expenses do not correlate to the ratio of expenses to average net assets shown in the Fund’s Financial Highlights, which does not include Acquired Fund Fees and Expenses.
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year, that the Fund’s operating expenses remain the same, and that you redeem all of your shares at the end of those periods. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	PRINCIPAL INVESTMENT STRATEGIES
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its objective by investing in a diversified portfolio of stocks and bonds. In seeking to achieve the Fund’s long-term capital growth objective, the Fund invests in common stocks of growth companies. To provide shareholders with regular income, the Fund invests in fixed-income securities and/or common stocks selected primarily for their dividend payment potential. Between 35% and 65% of the Fund’s assets will be invested in common stocks and between 35% and 65% in fixed-income securities. The Fund’s allocation of assets will vary over time in response to the Adviser’s evaluation of present and anticipated market and economic conditions. The equity portion of the Fund’s portfolio is invested primarily in the common stocks of growth companies with a capitalization of $5 billion or more at the time of purchase. In selecting equity securities for the Fund, the Adviser invests in growth-oriented companies it believes exhibit the potential for superior growth. The Adviser believes that a company’s earnings growth is the primary determinant of its potential long-term return and evaluates a company’s potential for above average long-term earnings and revenue growth. Several factors are considered in the Adviser’s evaluation of a company, including: unique product or service, growing product demand, dominant and growing market share, management experience and capabilities, and strong financial condition. When selling equity securities for the Fund, the Adviser considers several factors, including changes in a company’s fundamentals and anticipated earnings. The fixed-income portion of the Fund’s portfolio is invested primarily in a diversified portfolio of debt securities that may include the following securities: mortgage-backed securities (including collateralized mortgage obligations), such as securities issued by Government National Mortgage Association (GNMA securities are backed by the full faith and credit of the U.S. government), Federal Home Loan Mortgage Corporation (FHLMC) and Federal National Mortgage Association (FNMA) (FHLMC and FNMA securities are backed by the credit of the issuing governmental agency), asset-backed securities collateralized by assets such as automobile and credit card receivables, utilities, home improvement loans and home equity loans, obligations of the U.S. government, its agencies and instrumentalities, corporate debt securities, taxable municipal securities, and short-term debt obligations, including commercial paper and bank instruments, such as certificates of deposit, time deposits, and bankers’ acceptances. The Fund invests primarily in debt securities that, at the time of purchase, are either rated investment-grade (BBB or above by Standard & Poor’s or Baa or above by Moody’s Investor Services), or, if unrated, determined to be of comparable quality by the Adviser. Unrated securities will not exceed 20% of the fixed-income portion of the Fund’s portfolio. As of September 30, 2012, 1.9% of the fixed-income portion of the Fund’s portfolio was in unrated securities. In selecting fixed-income securities for the Fund, the Adviser seeks fixed-income securities providing maximum total return. In making purchase and sales decisions for the Fund, the Adviser considers its economic outlook and interest rate forecast, as well as its evaluation of a fixed-income security’s credit quality, yield, maturity, and liquidity. Based upon its economic outlook, the Adviser attempts to shift the fixed-income sector concentrations of the portfolio. Based upon its interest rate forecast, the Adviser attempts to shift the fixed-income portfolio’s average effective duration, seeking to maintain an average effective duration for the fixed-income portion of the Fund’s portfolio of 3 to 7 years. Duration is a measure of estimated price sensitivity relative to changes in interest rates. Portfolios with longer durations are typically more sensitive to changes in interest rates. For example, if interest rates rise by 1%, the market value of a security with an effective duration of 3 years would decrease by 3%, with all other factors being constant.
Risk [Heading]	rr_RiskHeading	PRINCIPAL INVESTMENT RISKS
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	You could lose money by investing in the Fund. The principal risks of investing in the Fund are as follows: Call Risk: Many bonds may be redeemed (“called”) at the option of the issuer before their stated maturity date. In general, an issuer will call its bonds if they can be refinanced by issuing new bonds which bear a lower interest rate. The Fund may then be forced to invest the unanticipated proceeds at lower interest rates, resulting in a decline in the Fund’s income. Credit Risk: The issuers or guarantors of securities of fixed-income securities owned by the Fund may default on the payment of principal or interest, or experience a decline in credit quality, causing the value of the Fund to decrease. Growth Style Investing Risk: Different types of stocks tend to shift into and out of favor with stock market investors depending on market and economic conditions. The Fund invests in growth style stocks. The Fund’s performance may at times be better or worse than the performance of funds that focus on other types of stocks or that have a broader investment style. Income Risk: The income you earn from the Fund may decline due to declining interest rates. Interest Rate Risk: An increase in interest rates may lower the Fund’s value and the overall return on your investment. The magnitude of this decrease is often greater for longer-term fixed income securities than shorter-term securities. Management Risk: A strategy used by the investment management team may not produce the intended results. Market Risk: The market value of securities may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, or the market as a whole. The market value of securities may fluctuate, sometimes rapidly and unpredictably. Mid Cap Stock Risk: Stocks of mid cap stocks may be subject to more abrupt or erratic market movements than stocks of larger, more established companies. Prepayment and Extension Risk: Declining interest rates may compel borrowers to prepay mortgages and debt obligations underlying the mortgage-backed and asset-backed securities owned by the Fund. The proceeds received by the Fund from prepayments will likely be reinvested at interest rates lower than the original investment, thus resulting in a reduction of income to the Fund. Likewise, rising interest rates could reduce prepayments and extend the life of securities with lower interest rates, which may increase the sensitivity of the Fund’s value to rising interest rates.
Risk Lose Money [Text]	rr_RiskLoseMoney	You could lose money by investing in the Fund.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	HISTORICAL PERFORMANCE
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide information on the Fund’s volatility and performance. The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future. The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark indices which are broad measures of market performance. Updated performance information is available at the Fund’s website at www.sitfunds.com or by calling 800-332-5580. After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark indices which are broad measures of market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	800-332-5580
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.sitfunds.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Annual Total Returns for calendar years ended December 31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The Fund’s year-to-date return as of 9/30/12 (not annualized) was 10.49%. Best Quarter: 11.54% (3Q09) Worst Quarter: -15.45% (4Q08)
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns for periods ended December 31, 2011
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Sit Balanced Fund | Sit Balanced Fund
Risk/Return:	rr_RiskReturnAbstract
Shareholder Fees (fees paid directly from your investment)	rr_MaximumAccountFee	none
Management Fees	rr_ManagementFeesOverAssets	1.00%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.01%	[1]
1 Year	rr_ExpenseExampleYear01	104
3 Years	rr_ExpenseExampleYear03	323
5 Years	rr_ExpenseExampleYear05	560
10 Years	rr_ExpenseExampleYear10	1,241
2002	rr_AnnualReturn2002	(18.59%)
2003	rr_AnnualReturn2003	19.20%
2004	rr_AnnualReturn2004	9.22%
2005	rr_AnnualReturn2005	7.51%
2006	rr_AnnualReturn2006	7.88%
2007	rr_AnnualReturn2007	10.52%
2008	rr_AnnualReturn2008	(26.88%)
2009	rr_AnnualReturn2009	23.12%
2010	rr_AnnualReturn2010	10.51%
2011	rr_AnnualReturn2011	2.04%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2012
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	10.49%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	11.54%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(15.45%)
1 Year	rr_AverageAnnualReturnYear01	2.04%
5 Years	rr_AverageAnnualReturnYear05	2.33%
10 Years	rr_AverageAnnualReturnYear10	3.27%
Sit Balanced Fund | Return after taxes on distributions | Sit Balanced Fund
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	1.71%
5 Years	rr_AverageAnnualReturnYear05	1.72%
10 Years	rr_AverageAnnualReturnYear10	2.63%
Sit Balanced Fund | Return after taxes on distributions and sale of Fund shares | Sit Balanced Fund
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	1.56%
5 Years	rr_AverageAnnualReturnYear05	1.70%
10 Years	rr_AverageAnnualReturnYear10	2.48%
Sit Balanced Fund | Barclays Capital Aggregate Bond Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	7.84%
5 Years	rr_AverageAnnualReturnYear05	6.50%
10 Years	rr_AverageAnnualReturnYear10	5.78%
Sit Balanced Fund | S&P 500 Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	2.11%
5 Years	rr_AverageAnnualReturnYear05	(0.25%)
10 Years	rr_AverageAnnualReturnYear10	2.92%

[1] The total annual fund operating expenses do not correlate to the ratio of expenses to average net assets shown in the Fund's Financial Highlights, which does not include Acquired Fund Fees and Expenses.

XML

Sit Balanced Fund

SUMMARY INFORMATION
SIT BALANCED FUND

INVESTMENT OBJECTIVE

The Fund seeks long-term capital growth consistent with preservation of principal and seeks to provide shareholders with regular income.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees (USD $)	Sit Balanced Fund
Shareholder Fees (fees paid directly from your investment)	none

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses		Sit Balanced Fund
Management Fees		1.00%
Acquired Fund Fees and Expenses	[1]	0.01%
Total Annual Fund Operating Expenses	[1]	1.01%

Example

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year, that the Fund’s operating expenses remain the same, and that you redeem all of your shares at the end of those periods. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:

Expense Example (USD $)	1 Year	3 Years	5 Years	10 Years
Sit Balanced Fund	104	323	560	1,241

PORTFOLIO TURNOVER

The Fund pays transactions costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 47.01% of the average value of the portfolio.

PRINCIPAL INVESTMENT STRATEGIES

The Fund seeks to achieve its objective by investing in a diversified portfolio of stocks and bonds. In seeking to achieve the Fund’s long-term capital growth objective, the Fund invests in common stocks of growth companies. To provide shareholders with regular income, the Fund invests in fixed-income securities and/or common stocks selected primarily for their dividend payment potential.

Between 35% and 65% of the Fund’s assets will be invested in common stocks and between 35% and 65% in fixed-income securities. The Fund’s allocation of assets will vary over time in response to the Adviser’s evaluation of present and anticipated market and economic conditions.

The equity portion of the Fund’s portfolio is invested primarily in the common stocks of growth companies with a capitalization of $5 billion or more at the time of purchase.

In selecting equity securities for the Fund, the Adviser invests in growth-oriented companies it believes exhibit the potential for superior growth. The Adviser believes that a company’s earnings growth is the primary determinant of its potential long-term return and evaluates a company’s potential for above average long-term earnings and revenue growth. Several factors are considered in the Adviser’s evaluation of a company, including:

• unique product or service,

• growing product demand,

• dominant and growing market share,

• management experience and capabilities, and

• strong financial condition.

When selling equity securities for the Fund, the Adviser considers several factors, including changes in a company’s fundamentals and anticipated earnings.

The fixed-income portion of the Fund’s portfolio is invested primarily in a diversified portfolio of debt securities that may include the following securities:

• mortgage-backed securities (including collateralized mortgage obligations), such as securities issued by Government National Mortgage Association (GNMA securities are backed by the full faith and credit of the U.S. government), Federal Home Loan Mortgage Corporation (FHLMC) and Federal National Mortgage Association (FNMA) (FHLMC and FNMA securities are backed by the credit of the issuing governmental agency),

• asset-backed securities collateralized by assets such as automobile and credit card receivables, utilities, home improvement loans and home equity loans,

• obligations of the U.S. government, its agencies and instrumentalities,

• corporate debt securities,

• taxable municipal securities, and

• short-term debt obligations, including commercial paper and bank instruments, such as certificates of deposit, time deposits, and bankers’ acceptances. The Fund invests primarily in debt securities that, at the time of purchase, are either rated investment-grade (BBB or above by Standard & Poor’s or Baa or above by Moody’s Investor Services), or, if unrated, determined to be of comparable quality by the Adviser. Unrated securities will not exceed 20% of the fixed-income portion of the Fund’s portfolio. As of September 30, 2012, 1.9% of the fixed-income portion of the Fund’s portfolio was in unrated securities.

In selecting fixed-income securities for the Fund, the Adviser seeks fixed-income securities providing maximum total return. In making purchase and sales decisions for the Fund, the Adviser considers its economic outlook and interest rate forecast, as well as its evaluation of a fixed-income security’s credit quality, yield, maturity, and liquidity. Based upon its economic outlook, the Adviser attempts to shift the fixed-income sector concentrations of the portfolio. Based upon its interest rate forecast, the Adviser attempts to shift the fixed-income portfolio’s average effective duration, seeking to maintain an average effective duration for the fixed-income portion of the Fund’s portfolio of 3 to 7 years. Duration is a measure of estimated price sensitivity relative to changes in interest rates. Portfolios with longer durations are typically more sensitive to changes in interest rates. For example, if interest rates rise by 1%, the market value of a security with an effective duration of 3 years would decrease by 3%, with all other factors being constant.

PRINCIPAL INVESTMENT RISKS

You could lose money by investing in the Fund. The principal risks of investing in the Fund are as follows:

• Call Risk: Many bonds may be redeemed (“called”) at the option of the issuer before their stated maturity date. In general, an issuer will call its bonds if they can be refinanced by issuing new bonds which bear a lower interest rate. The Fund may then be forced to invest the unanticipated proceeds at lower interest rates, resulting in a decline in the Fund’s income.

• Credit Risk: The issuers or guarantors of securities of fixed-income securities owned by the Fund may default on the payment of principal or interest, or experience a decline in credit quality, causing the value of the Fund to decrease.

• Growth Style Investing Risk: Different types of stocks tend to shift into and out of favor with stock market investors depending on market and economic conditions. The Fund invests in growth style stocks. The Fund’s performance may at times be better or worse than the performance of funds that focus on other types of stocks or that have a broader investment style.

• Income Risk: The income you earn from the Fund may decline due to declining interest rates.

• Interest Rate Risk: An increase in interest rates may lower the Fund’s value and the overall return on your investment. The magnitude of this decrease is often greater for longer-term fixed income securities than shorter-term securities.

• Management Risk: A strategy used by the investment management team may not produce the intended results.

• Market Risk: The market value of securities may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, or the market as a whole. The market value of securities may fluctuate, sometimes rapidly and unpredictably.

• Mid Cap Stock Risk: Stocks of mid cap stocks may be subject to more abrupt or erratic market movements than stocks of larger, more established companies.

• Prepayment and Extension Risk: Declining interest rates may compel borrowers to prepay mortgages and debt obligations underlying the mortgage-backed and asset-backed securities owned by the Fund. The proceeds received by the Fund from prepayments will likely be reinvested at interest rates lower than the original investment, thus resulting in a reduction of income to the Fund. Likewise, rising interest rates could reduce prepayments and extend the life of securities with lower interest rates, which may increase the sensitivity of the Fund’s value to rising interest rates.

HISTORICAL PERFORMANCE

The following bar chart and table provide information on the Fund’s volatility and performance. The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future. The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark indices which are broad measures of market performance. Updated performance information is available at the Fund’s website at www.sitfunds.com or by calling 800-332-5580.

After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

Annual Total Returns for calendar years ended December 31

The Fund’s year-to-date return as of 9/30/12 (not annualized) was 10.49%.
Best Quarter: 11.54% (3Q09)
Worst Quarter: -15.45% (4Q08)

Average Annual Total Returns for periods ended December 31, 2011

Average Annual Total Returns	1 Year	5 Years	10 Years
Sit Balanced Fund	2.04%	2.33%	3.27%
Sit Balanced Fund Return after taxes on distributions	1.71%	1.72%	2.63%
Sit Balanced Fund Return after taxes on distributions and sale of Fund shares	1.56%	1.70%	2.48%
Sit Balanced Fund Barclays Capital Aggregate Bond Index (reflects no deduction for fees, expenses or taxes)	7.84%	6.50%	5.78%
Sit Balanced Fund S&P 500 Index (reflects no deduction for fees, expenses or taxes)	2.11%	(0.25%)	2.92%

[1] The total annual fund operating expenses do not correlate to the ratio of expenses to average net assets shown in the Fund's Financial Highlights, which does not include Acquired Fund Fees and Expenses.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SIT MUTUAL FUNDS INC
Prospectus Date	rr_ProspectusDate	Nov. 01, 2012
Sit Global Dividend Growth Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	SUMMARY INFORMATION SIT GLOBAL DIVIDEND GROWTH FUND
Objective [Heading]	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks to provide current income that exceeds the dividend yield of a composite index (comprised of 60% S&P 500 Index and 40% MSCI EAFE Index) and that grows over a period of years.
Objective, Secondary [Text Block]	rr_ObjectiveSecondaryTextBlock	Secondarily the Fund seeks long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	FEES AND EXPENSES OF THE FUND
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	PORTFOLIO TURNOVER
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transactions costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 26.65% (both classes) of the average value of the portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	26.65%
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	The total annual fund operating expenses do not correlate to the ratio of expenses to average net assets shown in the Fund’s Financial Highlights, which does not include Acquired Fund Fees and Expenses.
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year, that the Fund’s operating expenses remain the same, and that you redeem all of your shares at the end of those periods. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	PRINCIPAL INVESTMENT STRATEGIES
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its objectives by investing, under normal market conditions, at least 80% of its net assets in dividend-paying common stocks issued by U.S. and foreign companies. The Fund may invest the balance of its assets in preferred stocks, convertible bonds, and U.S. Treasury securities. The Fund’s diversified portfolio is designed to have lower volatility than that of a composite index comprised of 60% S&P 500 Index and 40% MSCI EAFE Index (the “Composite Index”), but with a higher yield and greater prospects for dividend growth. The Adviser invests in dividend paying growth-oriented companies it believes exhibit the potential for growth and growing dividend payments. The Adviser believes that a company’s earnings growth is a primary determinant of its potential long-term return, and that a record of increasing dividend payments is a strong indicator of financial health and growth prospects. By investing in dividend paying stocks it is anticipated that the holdings will tend to be in large to medium-sized companies (companies with market capitalization in excess of $2 billion). The Adviser considers several factors in its evaluation of a company’s potential for above average long-term earnings, revenue, and dividend growth, including: a record of paying dividends, strong prospects for growing dividend payments indicated in part by growing earnings and cash flow, unique product or service, growing product demand, dominant and growing market share, management experience and capabilities, and strong financial condition. Since stocks that pay dividends tend to be less volatile and may not experience the same capital appreciation as stocks that don’t pay dividends, the Fund’s diversified portfolio of dividend paying stocks is expected to have lower volatility than that of the Composite Index, but with a higher dividend yield and greater prospects for dividend growth. The Fund diversifies its investments among a number of different countries throughout the world, but not fewer than three countries. Under normal market conditions, the Fund will invest significantly (at least 30% of its net assets) in companies outside the U.S. When selling equity securities for the Fund, the Adviser considers several factors, including changes in the company’s fundamentals, anticipated earnings, anticipated dividend payments and financial position.
Risk [Heading]	rr_RiskHeading	PRINCIPAL INVESTMENT RISKS
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	You could lose money by investing in the Fund. The principal risks of investing in the Fund are as follows: Developing Markets Risk: Investment in developing markets are subject to unique political, economic, and market risks that can cause the Fund’s investments to be more volatile and less liquid than investments in developed markets. Dividend Paying Company Risk: The Fund’s income objective may limit its ability to appreciate during a broad market advance because dividend paying stocks may not experience the same capital appreciation as non-dividend paying stocks. In addition, stocks held by the Fund may reduce or stop paying dividends which could affect the Fund’s ability to generate income. Growth Style Investing Risk: Different types of stocks tend to shift into and out of favor with stock market investors depending on market and economic conditions. The Fund invests in growth style stocks. The Fund’s performance may at times be better or worse than the performance of funds that focus on other types of stocks or that have a broader investment style. International Investing Risk: International investing involves risks not typically associated with investing in U.S. securities which may adversely affect the Fund’s investment. These risks include currency risk, foreign securities market risk, foreign tax risk, information risk, investment restriction risk, and political and economic risks. Management Risk: A strategy used by the investment management team may not produce the intended results. Market Risk: The market value of securities may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, or the market as a whole. The market value of securities may fluctuate, sometimes rapidly and unpredictably. Mid Cap Stock Risk: Stocks of mid cap stocks may be subject to more abrupt or erratic market movement than stocks of larger, more established companies.
Risk Lose Money [Text]	rr_RiskLoseMoney	You could lose money by investing in the Fund.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	HISTORICAL PERFORMANCE
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide information on the Fund’s volatility and performance. The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future. The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for Class I shares. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance. Updated performance information is available at the Fund’s website at www.sitfunds.com or by calling 800-332-5580. After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown only for Class I shares; after-tax returns for Class S shares will vary.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for Class I shares. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	800-332-5580
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.sitfunds.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Annual Total Returns for calendar years ended December 31 (Class I)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The Fund’s year-to-date return as of 9/30/12 (not annualized) was 11.94% Best Quarter: 16.30% (2Q09) Worst Quarter: -16.65% (3Q11)
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns for periods ended December 31, 2011
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax returns are shown only for Class I shares; after-tax returns for Class S shares will vary.
Sit Global Dividend Growth Fund | Class I
Risk/Return:	rr_RiskReturnAbstract
Redemption Fee (as a percentage of amount redeemed only on shares held for less than 30 days)	rr_RedemptionFeeOverRedemption	2.00%
Management Fees	rr_ManagementFeesOverAssets	1.25%
Distribution (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.07%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.32%	[1]
1 Year	rr_ExpenseExampleYear01	135
3 Years	rr_ExpenseExampleYear03	421
5 Years	rr_ExpenseExampleYear05	728
10 Years	rr_ExpenseExampleYear10	1,598
2008	rr_AnnualReturn2008	(5.25%)
2009	rr_AnnualReturn2009	24.65%
2010	rr_AnnualReturn2010	11.58%
2011	rr_AnnualReturn2011	(2.58%)
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2012
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	11.94%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	16.30%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2011
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(16.65%)
1 Year	rr_AverageAnnualReturnYear01	(2.58%)
Life of Fund	rr_AverageAnnualReturnSinceInception	7.98%
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 30, 2008
Sit Global Dividend Growth Fund | Class S
Risk/Return:	rr_RiskReturnAbstract
Redemption Fee (as a percentage of amount redeemed only on shares held for less than 30 days)	rr_RedemptionFeeOverRedemption	2.00%
Management Fees	rr_ManagementFeesOverAssets	1.25%
Distribution (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.07%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.57%	[1]
1 Year	rr_ExpenseExampleYear01	161
3 Years	rr_ExpenseExampleYear03	499
5 Years	rr_ExpenseExampleYear05	861
10 Years	rr_ExpenseExampleYear10	1,878
1 Year	rr_AverageAnnualReturnYear01	(2.89%)
Life of Fund	rr_AverageAnnualReturnSinceInception	7.70%
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 30, 2008
Sit Global Dividend Growth Fund | Return after taxes on distributions | Class I
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(2.98%)
Life of Fund	rr_AverageAnnualReturnSinceInception	7.62%
Sit Global Dividend Growth Fund | Return after taxes on distributions and sale of Fund shares | Class I
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.15%)
Life of Fund	rr_AverageAnnualReturnSinceInception	6.84%
Sit Global Dividend Growth Fund | S&P 500 Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	2.11%
Life of Fund	rr_AverageAnnualReturnSinceInception	4.66%
Sit Global Dividend Growth Fund | MSCI EAFE Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(12.14%)
Life of Fund	rr_AverageAnnualReturnSinceInception	(0.04%)

[1] The total annual fund operating expenses do not correlate to the ratio of expenses to average net assets shown in the Fund's Financial Highlights, which does not include Acquired Fund Fees and Expenses.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SIT MUTUAL FUNDS INC
Prospectus Date	rr_ProspectusDate	Nov. 01, 2012
SIT MID CAP GROWTH FUND INC | SIT MID CAP GROWTH FUND INC
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	SUMMARY INFORMATION SIT MID CAP GROWTH FUND
Objective [Heading]	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks to maximize long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	FEES AND EXPENSES OF THE FUND
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	PORTFOLIO TURNOVER
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transactions costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 16.23% of the average value of the portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	16.23%
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year, that the Fund’s operating expenses remain the same, and that you redeem all of your shares at the end of those periods. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	PRINCIPAL INVESTMENT STRATEGIES
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its objective by investing, under normal market conditions, at least 80% of its net assets in the common stocks of companies with capitalizations of $2 billion to $15 billion at the time of purchase. The Adviser invests in domestic growth-oriented medium to small companies it believes exhibit the potential for superior growth. The Adviser believes that a company’s earnings growth is the primary determinant of its potential long-term return and evaluates a company’s potential for above average long-term earnings and revenue growth. Several factors are considered in the Adviser’s evaluation of a company, including: unique product or service, growing product demand, dominant and growing market share, management experience and capabilities, and strong financial condition. When selling equity securities for the Fund, the Adviser considers several factors, including changes in a company’s fundamentals and anticipated earnings.
Risk [Heading]	rr_RiskHeading	PRINCIPAL INVESTMENT RISKS
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	You could lose money by investing in the Fund. The principal risks of investing in the Fund are as follows: Growth Style Investing Risk: Different types of stocks tend to shift into and out of favor with stock market investors depending on market and economic conditions. The Fund invests in growth style stocks. The Fund’s performance may at times be better or worse than the performance of funds that focus on other types of stocks or that have a broader investment style. Management Risk: A strategy used by the investment management team may not produce the intended results. Market Risk: The market value of securities may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, or the market as a whole. The market value of securities may fluctuate, sometimes rapidly and unpredictably. Mid Cap Stock Risk: Stocks of mid cap stocks may be subject to more abrupt or erratic market movements than stocks of larger, more established companies.
Risk Lose Money [Text]	rr_RiskLoseMoney	You could lose money by investing in the Fund.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	HISTORICAL PERFORMANCE
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide information on the Fund’s volatility and performance. The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future. The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance. Updated performance information is available at the Fund’s website at www.sitfunds.com or by calling 800-332-5580. The table includes returns both before and after taxes. After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	800-332-5580
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.sitfunds.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Annual Total Returns for calendar years ended December 31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The Fund’s year-to-date return as of 9/30/12 (not annualized) was 15.47%. Best Quarter: 19.71% (2Q09) Worst Quarter: -26.99% (4Q08)
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns for periods ended December 31, 2011
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
SIT MID CAP GROWTH FUND INC | SIT MID CAP GROWTH FUND INC | SIT MID CAP GROWTH FUND INC
Risk/Return:	rr_RiskReturnAbstract
Redemption Fee (as a percentage of amount redeemed only on shares held for less than 30 days)	rr_RedemptionFeeOverRedemption	2.00%
Management Fees	rr_ManagementFeesOverAssets	1.25%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.25%
1 Year	rr_ExpenseExampleYear01	128
3 Years	rr_ExpenseExampleYear03	399
5 Years	rr_ExpenseExampleYear05	690
10 Years	rr_ExpenseExampleYear10	1,518
2002	rr_AnnualReturn2002	(34.64%)
2003	rr_AnnualReturn2003	38.51%
2004	rr_AnnualReturn2004	17.02%
2005	rr_AnnualReturn2005	15.27%
2006	rr_AnnualReturn2006	9.56%
2007	rr_AnnualReturn2007	18.87%
2008	rr_AnnualReturn2008	(45.34%)
2009	rr_AnnualReturn2009	35.59%
2010	rr_AnnualReturn2010	27.10%
2011	rr_AnnualReturn2011	(6.53%)
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2012
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	15.47%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	19.71%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(26.99%)
1 Year	rr_AverageAnnualReturnYear01	(6.53%)
5 Years	rr_AverageAnnualReturnYear05	0.91%
10 Years	rr_AverageAnnualReturnYear10	3.42%
SIT MID CAP GROWTH FUND INC | SIT MID CAP GROWTH FUND INC | Return after taxes on distributions | SIT MID CAP GROWTH FUND INC
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(6.53%)
5 Years	rr_AverageAnnualReturnYear05	0.79%
10 Years	rr_AverageAnnualReturnYear10	3.36%
SIT MID CAP GROWTH FUND INC | SIT MID CAP GROWTH FUND INC | Return after taxes on distributions and sale of Fund shares | SIT MID CAP GROWTH FUND INC
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(4.24%)
5 Years	rr_AverageAnnualReturnYear05	0.78%
10 Years	rr_AverageAnnualReturnYear10	2.97%
SIT MID CAP GROWTH FUND INC | SIT MID CAP GROWTH FUND INC | Russell Mid Cap Growth Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.65%)
5 Years	rr_AverageAnnualReturnYear05	2.44%
10 Years	rr_AverageAnnualReturnYear10	5.29%

XML

Document and Entity Information	12 Months Ended
	Nov. 01, 2012
Risk/Return:
Document Type	485BPOS
Document Period End Date	Jun. 30, 2012
Registrant Name	SIT MUTUAL FUNDS INC
Central Index Key	0000877880
Amendment Flag	false
Document Creation Date	Oct. 29, 2012
Document Effective Date	Nov. 01, 2012
Prospectus Date	Nov. 01, 2012

XML

SIT LARGE CAP GROWTH FUND INC | SIT LARGE CAP GROWTH FUND INC

SUMMARY INFORMATION
SIT LARGE CAP GROWTH FUND

INVESTMENT OBJECTIVE

The Fund seeks to maximize long-term capital appreciation.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees	SIT LARGE CAP GROWTH FUND INC
Redemption Fee (as a percentage of amount redeemed only on shares held for less than 30 days)	2.00%

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses	SIT LARGE CAP GROWTH FUND INC
Management Fees	1.00%
Total Annual Fund Operating Expenses	1.00%

Example

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year, that the Fund’s operating expenses remain the same, and that you redeem all of your shares at the end of those periods. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:

Expense Example (USD $)	1 Year	3 Years	5 Years	10 Years
SIT LARGE CAP GROWTH FUND INC	103	320	555	1,229

PORTFOLIO TURNOVER

The Fund pays transactions costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 15.06% of the average value of the portfolio.

PRINCIPAL INVESTMENT STRATEGIES

The Fund seeks to achieve its objective by investing, under normal market conditions, at least 80% of its net assets in the common stocks of companies with capitalizations of $5 billion or more at the time of purchase.

The Adviser invests in domestic growth-oriented companies it believes exhibit the potential for superior growth. The Fund focuses on stocks issued by companies with long records of earnings and revenue growth. The Adviser believes that a company’s earnings growth is the primary determinant of its potential long-term return and evaluates a company’s potential for above average long-term earnings and revenue growth. Several factors are considered in the Adviser’s evaluation of a company, including:

• unique product or service,

• growing product demand,

• dominant and growing market share,

• management experience and capabilities, and

• strong financial condition.

When selling equity securities for the Fund, the Adviser considers several factors, including changes in a company’s fundamentals and anticipated earnings.

PRINCIPAL INVESTMENT RISKS

You could lose money by investing in the Fund. The principal risks of investing in the Fund are as follows:

• Growth Style Investing Risk: Different types of stocks tend to shift into and out of favor with stock market investors depending on market and economic conditions. The Fund invests in growth style stocks. The Fund’s performance may at times be better or worse than the performance of funds that focus on other types of stocks or that have a broader investment style.

• Management Risk: A strategy used by the investment management team may not produce the intended results.

• Market Risk: The market value of securities may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, or the market as a whole. The market value of securities may fluctuate, sometimes rapidly and unpredictably.

HISTORICAL PERFORMANCE

The following bar chart and table provide information on the Fund’s volatility and performance. The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future. The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance. Updated performance information is available at the Fund’s website at www.sitfunds.com or by calling 800-332-5580.

After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

Annual Total Returns for calendar years ended December 31

The Fund’s year-to-date return as of 9/30/12 (not annualized) was 15.92%.
Best Quarter: 14.50% (2Q03)
Worst Quarter: -21.13% (4Q08)

Average Annual Total Returns for periods ended December 31, 2011

Average Annual Total Returns	1 Year	5 Years	10 Years
SIT LARGE CAP GROWTH FUND INC	(0.53%)	1.22%	2.35%
SIT LARGE CAP GROWTH FUND INC Return after taxes on distributions	(0.64%)	1.13%	2.29%
SIT LARGE CAP GROWTH FUND INC Return after taxes on distributions and sale of Fund shares	(0.19%)	1.03%	2.02%
SIT LARGE CAP GROWTH FUND INC Russell 1000 Growth Index (reflects no deduction for fees, expenses or taxes)	2.64%	2.50%	2.60%

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SIT MUTUAL FUNDS INC
Prospectus Date	rr_ProspectusDate	Nov. 01, 2012
Sit Dividend Growth Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	SUMMARY INFORMATION SIT DIVIDEND GROWTH FUND
Objective [Heading]	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund primarily seeks to provide current income that exceeds the dividend yield of the S&P 500 Index and that grows over a period of years.
Objective, Secondary [Text Block]	rr_ObjectiveSecondaryTextBlock	Secondarily the Fund seeks long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	FEES AND EXPENSES OF THE FUND
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	PORTFOLIO TURNOVER
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transactions costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 26.84% (both classes) of the average value of the portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	26.84%
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	The total annual fund operating expenses do not correlate to the ratio of expenses to average net assets shown in the Fund’s Financial Highlights, which does not include Acquired Fund Fees and Expenses.
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year, that the Fund’s operating expenses remain the same, and that you redeem all of your shares at the end of those periods. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	PRINCIPAL INVESTMENT STRATEGIES
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its objectives by investing, under normal market conditions, at least 80% of its net assets in dividend-paying common stocks. The Fund may invest the balance of its assets in preferred stocks, convertible bonds, and U.S. Treasury securities. The Adviser invests in dividend paying growth-oriented companies it believes exhibit the potential for growth and growing dividend payments. The Adviser believes that a company’s earnings growth is a primary determinant of its potential long-term return, and that a record of increasing dividend payments is a strong indicator of financial health and growth prospects. By investing in dividend paying stocks it is anticipated that the holdings will tend to be in large to medium-sized companies (companies with market capitalizations in excess of $2 billion). The Adviser considers several factors in its evaluation of a company’s potential for above average long-term earnings, revenue, and dividend growth, including: a record of paying dividends, strong prospects for growing dividend payments indicated in part by growing earnings and cash flow, unique product or service, growing product demand, dominant and growing market share, management experience and capabilities, and strong financial condition. Since stocks that pay dividends tend to be less volatile and may not experience the same capital appreciation as stocks that don’t pay dividends, the Fund’s diversified portfolio of dividend paying stocks is expected to have lower volatility than that of the S&P 500 Index, but with a higher dividend yield and greater prospects for dividend growth. The Fund may invest up to 20% of its net assets in securities of issuers domiciled outside the U.S. When selling equity securities for the Fund, the Adviser considers several factors, including changes in a company’s fundamentals, anticipated earnings, anticipated dividend payments and financial position.
Risk [Heading]	rr_RiskHeading	PRINCIPAL INVESTMENT RISKS
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	You could lose money by investing in the Fund. The principal risks of investing in the Fund are as follows: Dividend Paying Company Risk: The Fund’s income objective may limit its ability to appreciate during a broad market advance because dividend paying stocks may not experience the same capital appreciation as non-dividend paying stocks. In addition, stocks held by the Fund may reduce or stop paying dividends which could affect the Fund’s ability to generate income. Growth Style Investing Risk: Different types of stocks tend to shift into and out of favor with stock market investors depending on market and economic conditions. The Fund invests in growth style stocks. The Fund’s performance may at times be better or worse than the performance of funds that focus on other types of stocks or that have a broader investment style. International Investing Risk: Because the Fund may invest in foreign securities, there is an international investing risk. International investing involves risks not typically associated with investing in U.S. securities which may adversely affect the Fund’s investment. These risks include currency risk, foreign securities market risk, foreign tax risk, information risk, investment restriction risk, and political and economic risks. Management Risk: A strategy used by the investment management team may not produce the intended results. Market Risk: The market value of securities may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, or the market as a whole. The market value of securities may fluctuate, sometimes rapidly and unpredictably. Mid Cap Stock Risk: Stocks of mid cap stocks may be subject to more abrupt or erratic market movement than stocks of larger, more established companies.
Risk Lose Money [Text]	rr_RiskLoseMoney	You could lose money by investing in the Fund.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	HISTORICAL PERFORMANCE
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide information on the Fund’s volatility and performance. The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future. The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for Class I shares. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance. Updated performance information is available at the Fund’s website at www.sitfunds.com or by calling 800-332-5580. After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown only for Class I shares; after-tax returns for Class S shares will vary.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for Class I shares. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	800-332-5580
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.sitfunds.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Annual Total Returns for calendar years ended December 31 (Class I)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The Fund’s year-to-date return as of 9/30/12 (not annualized) was 13.62%. Best Quarter: 14.44% (2Q09) Worst Quarter: -19.13% (4Q08)
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns for periods ended December 31, 2011
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax returns are shown only for Class I shares; after-tax returns for Class S shares will vary.
Sit Dividend Growth Fund | Class I
Risk/Return:	rr_RiskReturnAbstract
Redemption Fee (as a percentage of amount redeemed only on shares held for less than 30 days)	rr_RedemptionFeeOverRedemption	2.00%
Management Fees	rr_ManagementFeesOverAssets	1.00%
Distribution (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.15%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.15%	[1]
1 Year	rr_ExpenseExampleYear01	118
3 Years	rr_ExpenseExampleYear03	367
5 Years	rr_ExpenseExampleYear05	636
10 Years	rr_ExpenseExampleYear10	1,404
2004	rr_AnnualReturn2004	10.91%
2005	rr_AnnualReturn2005	9.41%
2006	rr_AnnualReturn2006	18.29%
2007	rr_AnnualReturn2007	12.89%
2008	rr_AnnualReturn2008	(29.60%)
2009	rr_AnnualReturn2009	25.59%
2010	rr_AnnualReturn2010	16.43%
2011	rr_AnnualReturn2011	3.29%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2012
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	13.62%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter:
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	14.44%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter:
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(19.13%)
1 Year	rr_AverageAnnualReturnYear01	3.29%
5 Years	rr_AverageAnnualReturnYear05	3.72%
Life of Fund	rr_AverageAnnualReturnSinceInception	7.03%
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 31, 2003
Sit Dividend Growth Fund | Class S
Risk/Return:	rr_RiskReturnAbstract
Redemption Fee (as a percentage of amount redeemed only on shares held for less than 30 days)	rr_RedemptionFeeOverRedemption	2.00%
Management Fees	rr_ManagementFeesOverAssets	1.00%
Distribution (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.15%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.40%	[1]
1 Year	rr_ExpenseExampleYear01	144
3 Years	rr_ExpenseExampleYear03	446
5 Years	rr_ExpenseExampleYear05	771
10 Years	rr_ExpenseExampleYear10	1,689
1 Year	rr_AverageAnnualReturnYear01	2.98%
5 Years	rr_AverageAnnualReturnYear05	3.45%
Life of Fund	rr_AverageAnnualReturnSinceInception	4.91%
Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 31, 2006
Sit Dividend Growth Fund | Return after taxes on distributions | Class I
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	2.95%
5 Years	rr_AverageAnnualReturnYear05	3.11%
Life of Fund	rr_AverageAnnualReturnSinceInception	6.48%
Sit Dividend Growth Fund | Return after taxes on distributions and sale of Fund shares | Class I
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	2.59%
5 Years	rr_AverageAnnualReturnYear05	3.07%
Life of Fund	rr_AverageAnnualReturnSinceInception	6.04%
Sit Dividend Growth Fund | S&P 500 Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	2.11%
5 Years	rr_AverageAnnualReturnYear05	(0.25%)
Life of Fund	rr_AverageAnnualReturnSinceInception	3.63%

[1] The total annual fund operating expenses do not correlate to the ratio of expenses to average net assets shown in the Fund's Financial Highlights, which does not include Acquired Fund Fees and Expenses.

XML

Sit Global Dividend Growth Fund

SUMMARY INFORMATION
SIT GLOBAL DIVIDEND GROWTH FUND

INVESTMENT OBJECTIVE

The Fund seeks to provide current income that exceeds the dividend yield of a composite index (comprised of 60% S&P 500 Index and 40% MSCI EAFE Index) and that grows over a period of years.

Secondarily the Fund seeks long-term capital appreciation.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees Sit Global Dividend Growth Fund	Class I	Class S
Redemption Fee (as a percentage of amount redeemed only on shares held for less than 30 days)	2.00%	2.00%

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses Sit Global Dividend Growth Fund		Class I	Class S
Management Fees		1.25%	1.25%
Distribution (12b-1) fees		none	0.25%
Acquired Fund Fees and Expenses	[1]	0.07%	0.07%
Total Annual Fund Operating Expenses	[1]	1.32%	1.57%

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year, that the Fund’s operating expenses remain the same, and that you redeem all of your shares at the end of those periods. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:

Expense Example Sit Global Dividend Growth Fund (USD $)	1 Year	3 Years	5 Years	10 Years
Class I	135	421	728	1,598
Class S	161	499	861	1,878

PORTFOLIO TURNOVER

The Fund pays transactions costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 26.65% (both classes) of the average value of the portfolio.

PRINCIPAL INVESTMENT STRATEGIES

The Fund seeks to achieve its objectives by investing, under normal market conditions, at least 80% of its net assets in dividend-paying common stocks issued by U.S. and foreign companies. The Fund may invest the balance of its assets in preferred stocks, convertible bonds, and U.S. Treasury securities.

The Fund’s diversified portfolio is designed to have lower volatility than that of a composite index comprised of 60% S&P 500 Index and 40% MSCI EAFE Index (the “Composite Index”), but with a higher yield and greater prospects for dividend growth.

The Adviser invests in dividend paying growth-oriented companies it believes exhibit the potential for growth and growing dividend payments. The Adviser believes that a company’s earnings growth is a primary determinant of its potential long-term return, and that a record of increasing dividend payments is a strong indicator of financial health and growth prospects. By investing in dividend paying stocks it is anticipated that the holdings will tend to be in large to medium-sized companies (companies with market capitalization in excess of $2 billion).

The Adviser considers several factors in its evaluation of a company’s potential for above average long-term earnings, revenue, and dividend growth, including:

• a record of paying dividends,

• strong prospects for growing dividend payments indicated in part by growing earnings and cash flow,

• unique product or service,

• growing product demand,

• dominant and growing market share,

• management experience and capabilities, and

• strong financial condition.

Since stocks that pay dividends tend to be less volatile and may not experience the same capital appreciation as stocks that don’t pay dividends, the Fund’s diversified portfolio of dividend paying stocks is expected to have lower volatility than that of the Composite Index, but with a higher dividend yield and greater prospects for dividend growth.

The Fund diversifies its investments among a number of different countries throughout the world, but not fewer than three countries. Under normal market conditions, the Fund will invest significantly (at least 30% of its net assets) in companies outside the U.S.

When selling equity securities for the Fund, the Adviser considers several factors, including changes in the company’s fundamentals, anticipated earnings, anticipated dividend payments and financial position.

PRINCIPAL INVESTMENT RISKS

You could lose money by investing in the Fund. The principal risks of investing in the Fund are as follows:

• Developing Markets Risk: Investment in developing markets are subject to unique political, economic, and market risks that can cause the Fund’s investments to be more volatile and less liquid than investments in developed markets.

• Dividend Paying Company Risk: The Fund’s income objective may limit its ability to appreciate during a broad market advance because dividend paying stocks may not experience the same capital appreciation as non-dividend paying stocks. In addition, stocks held by the Fund may reduce or stop paying dividends which could affect the Fund’s ability to generate income.

• Growth Style Investing Risk: Different types of stocks tend to shift into and out of favor with stock market investors depending on market and economic conditions. The Fund invests in growth style stocks. The Fund’s performance may at times be better or worse than the performance of funds that focus on other types of stocks or that have a broader investment style.

• International Investing Risk: International investing involves risks not typically associated with investing in U.S. securities which may adversely affect the Fund’s investment. These risks include currency risk, foreign securities market risk, foreign tax risk, information risk, investment restriction risk, and political and economic risks.

• Management Risk: A strategy used by the investment management team may not produce the intended results.

• Market Risk: The market value of securities may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, or the market as a whole. The market value of securities may fluctuate, sometimes rapidly and unpredictably.

• Mid Cap Stock Risk: Stocks of mid cap stocks may be subject to more abrupt or erratic market movement than stocks of larger, more established companies.

HISTORICAL PERFORMANCE

The following bar chart and table provide information on the Fund’s volatility and performance. The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future. The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year for Class I shares. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance. Updated performance information is available at the Fund’s website at www.sitfunds.com or by calling 800-332-5580.

After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown only for Class I shares; after-tax returns for Class S shares will vary.

Annual Total Returns for calendar years ended December 31 (Class I)

The Fund’s year-to-date return as of 9/30/12 (not annualized) was 11.94%
Best Quarter: 16.30% (2Q09)
Worst Quarter: -16.65% (3Q11)

Average Annual Total Returns for periods ended December 31, 2011

Average Annual Total Returns Sit Global Dividend Growth Fund	1 Year	Life of Fund	Inception Date
Class I	(2.58%)	7.98%	Sep. 30, 2008
Class I Return after taxes on distributions	(2.98%)	7.62%
Class I Return after taxes on distributions and sale of Fund shares	(1.15%)	6.84%
Class S	(2.89%)	7.70%	Sep. 30, 2008
S&P 500 Index (reflects no deduction for fees, expenses or taxes)	2.11%	4.66%
MSCI EAFE Index (reflects no deduction for fees, expenses or taxes)	(12.14%)	(0.04%)

[1] The total annual fund operating expenses do not correlate to the ratio of expenses to average net assets shown in the Fund's Financial Highlights, which does not include Acquired Fund Fees and Expenses.

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Sit Developing Markets Growth Fund

SUMMARY INFORMATION
SIT DEVELOPING MARKETS GROWTH FUND

INVESTMENT OBJECTIVE

The Fund seeks to maximize long-term capital appreciation.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (fees paid directly from your investment)

Shareholder Fees	Sit Developing Markets Growth Fund
Redemption Fee (as a percentage of amount redeemed only on shares held for less than 30 days)	2.00%

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses		Sit Developing Markets Growth Fund
Management Fees		2.00%
Acquired Fund Fees and Expenses	[1]	0.01%
Total Annual Fund Operating Expenses	[1]	2.01%

Example

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year, that the Fund’s operating expenses remain the same, and that you redeem all of your shares at the end of those periods. Although your actual costs and returns may be higher or lower, based on these assumptions your costs would be:

Expense Example (USD $)	1 Year	3 Years	5 Years	10 Years
Sit Developing Markets Growth Fund	206	636	1,093	2,355

PORTFOLIO TURNOVER

The Fund pays transactions costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 22.56% of the average value of the portfolio.

PRINCIPAL INVESTMENT STRATEGIES

The Fund seeks to achieve its objective by investing, under normal market conditions, at least 80% of its net assets in common stocks of companies domiciled or operating in a developing market.

Developing markets are those countries that:

• have emerging stock markets as defined by the International Finance Corporation,

• have low-to middle-income economies according to the World Bank, or

• have similar developing characteristics, for example, countries in the MSCI EM Index and Hong Kong are considered to be developing.

As of September 30, 2012, the Fund held investments in Hong Kong, Philippines, South Korea, Taiwan, Thailand, Brazil, Mexico, South Africa, Australia, China, Singapore, Israel, Russia, India, Indonesia, Peru, Chile, Argentina, and Sweden. The Fund also held investments in companies domiciled in Great Britain, which have substantial business activities in developing markets.

In selecting investments for the Fund, the Adviser begins by selecting countries or regions in which to invest. In making its selections, the Adviser considers several factors affecting the economy and equity market of foreign countries and regions, including:

• economic trends,

• earnings outlook,

• liquidity within the market,

• fiscal and monetary policy,

• currency exchange rate expectations,

• investment valuation,

• market sentiment, and

• social and political trends.

After the country and regional allocations are determined, the Adviser seeks industries and sectors that appear to have strong earnings growth prospects. Within the selected industries and sectors, the Adviser invests in foreign growth-oriented companies it believes exhibit the potential for superior growth. The Adviser believes that a company’s earnings growth is the primary determinant of its potential long-term return and evaluates a company’s potential for above average long-term earnings and revenue growth. Several factors are considered in the Adviser’s evaluation of a company, including:

• unique product or service,

• growing product demand,

• regional or country dominance and growing market share,

• management experience and capabilities, and

• strong financial condition.

When selling equity securities for the Fund, the Adviser considers several factors, including changes in a company’s fundamentals and anticipated earnings.

The Fund invests in small, medium and large sized companies. Small companies generally have capitalizations of under $3.0 billion, and large companies generally have a capitalization greater than $5 billion. The Fund may invest in securities representing underlying international securities such as sponsored American Depository Receipts, European Depository Receipts and Global Depository Receipts.

In order to hedge against adverse movements in currency exchange rates, the Fund may from time to time enter into forward foreign currency exchange contracts.

PRINCIPAL INVESTMENT RISKS

• Developing Markets Risk: Investment in developing markets are subject to unique political, economic, and market risks that can cause the Fund’s investments to be more volatile and less liquid than investments in developed markets.

• Foreign Currency Hedging Transactions Risk: If the Adviser’s forecast of exchange rate movements is incorrect, the Fund may realize losses on their foreign currency transactions. In addition, the Fund’s hedging transactions may prevent the Funds from realizing the benefits of a favorable change in the value of foreign currencies.

• Growth Style Investing Risk: Different types of stocks tend to shift into and out of favor with stock market investors depending on market and economic conditions. The Fund invests in growth style stocks. The Fund’s performance may at times be better or worse than the performance of funds that focus on other types of stocks or that have a broader investment style.

• International Investing Risk: International investing involves risks not typically associated with investing in U.S. securities which may adversely affect the Fund’s investment. These risks include currency risk, foreign securities market risk, foreign tax risk, information risk, investment restriction risk, and political and economic risks.

• Management Risk: A strategy used by the investment management team may not produce the intended results.

• Market Risk: The market value of securities may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, or the market as a whole. The market value of securities may fluctuate, sometimes rapidly and unpredictably.

• Mid Cap Stock Risk: Stocks of mid cap stocks may be subject to more abrupt or erratic market movements than stocks of larger, more established companies.

• Small Cap Stock Risk: Stocks of smaller companies involve substantial risk. Prices of small cap stocks may be subject to more abrupt or erratic market movements than stocks of larger, more established companies. Additionally, for certain small cap stocks, there may also be limited liquidity, or trading opportunities at a favorable price or time.

HISTORICAL PERFORMANCE

The following bar chart and table provide information on the Fund’s volatility and performance. The Fund’s past performance before and after taxes is not necessarily an indication of how the Fund will perform in the future. The bar chart below is intended to provide you with an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The table below compares the Fund’s performance over different time periods to that of the Fund’s benchmark index, which is a broad measure of market performance. Updated performance information is available at the Fund’s website at www.sitfunds.com or by calling 800-332-5580.

After-tax returns are calculated using historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

Annual Total Returns for calendar years ended December 31

The Fund’s year-to-date return as of 9/30/12 (not annualized) was 5.29%.
Best Quarter: 32.98% (2Q09)
Worst Quarter: -30.73% (4Q08)

Average Annual Total Returns for periods ended December 31, 2011

Average Annual Total Returns	1 Year	5 Years	10 Years
Sit Developing Markets Growth Fund	(18.48%)	0.45%	9.59%
Sit Developing Markets Growth Fund Return after taxes on distributions	(19.58%)	(0.14%)	9.25%
Sit Developing Markets Growth Fund Return after taxes on distributions and sale of Fund shares	(10.58%)	0.34%	8.53%
Sit Developing Markets Growth Fund MSCI Emerging Markets Index (reflects no deduction for fees, expenses or taxes)	(20.41%)	0.08%	11.19%

[1] The total annual fund operating expenses do not correlate to the ratio of expenses to average net assets shown in the Fund's Financial Highlights, which does not include Acquired Fund Fees and Expenses.

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Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	SIT MUTUAL FUNDS INC
Prospectus Date	rr_ProspectusDate	Nov. 01, 2012
Document Creation Date	dei_DocumentCreationDate	Oct. 29, 2012