Before you invest, you may want to review the Fund’s Prospectus, which contains more information about the Fund and its risks. You can find the Fund’s Prospectus and other information about the Fund online at janus.com/info. You can also get this information at no cost by calling a Janus representative at 1-877-335-2687 or by sending an email request to prospectusrequest@janus.com. [INTECH LOGO] 

Summary Prospectus dated October 26, 2012

As Supplemented February 15, 2013

INTECH International Fund

Ticker:	JMIAX	Class A Shares	JMISX	Class S Shares	JRMTX	Class T Shares
	JMICX	Class C Shares	JMIIX	Class I Shares

INVESTMENT OBJECTIVE

INTECH International Fund seeks long-term growth of capital.

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. Each share class has different expenses, but represents an investment in the same Fund. For Class A Shares, you may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in the Fund or in other Janus mutual funds. More information about these and other discounts, as well as eligibility requirements for each share class, is available from your financial professional and in the “Purchases” section on page 46 of the Fund’s Prospectus and in the “Purchases” section on page 83 of the Fund’s Statement of Additional Information.

SHAREHOLDER FEES (fees paid directly from your investment)	Class A	Class C	Class S	Class I	Class T
Maximum Sales Charge (load) Imposed on Purchases (as a percentage of offering price)	5.75%	None	None	None	None
Maximum Deferred Sales Charge (load) (as a percentage of the lower of original purchase price or redemption proceeds)	None	1.00%	None	None	None
ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)	Class A	Class C	Class S	Class I	Class T
Management Fees	0.55%	0.55%	0.55%	0.55%	0.55%
Distribution/Service (12b-1) Fees	0.25%	1.00%	0.25%	None	None
Other Expenses	0.62%	0.70%	0.86%	0.58%	0.86%
Total Annual Fund Operating Expenses(1)	1.42%	2.25%	1.66%	1.13%	1.41%
Fee Waiver(1)	0.16%	0.24%	0.15%	0.12%	0.15%
Total Annual Fund Operating Expenses After Fee Waiver(1)	1.26%	2.01%	1.51%	1.01%	1.26%

(1)  Janus Capital has contractually agreed to waive the Fund’s total annual fund operating expenses (excluding the distribution and shareholder servicing fees – applicable to Class A Shares, Class C Shares, and Class S Shares; administrative services fees payable pursuant to the Transfer Agency Agreement (except for networking and omnibus fees for Class A Shares, Class C Shares, and Class I Shares); brokerage commissions; interest; dividends; taxes; acquired fund fees and expenses; and extraordinary expenses) to 1.00% until at least November 1, 2013. The contractual waiver may be terminated or modified prior to this date only at the discretion of the Board of Trustees.

EXAMPLE:

The following Example is based on expenses without waivers. The Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and reinvest all dividends and distributions. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses without waivers remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

If Shares are redeemed:	1 Year		3 Years		5 Years		10 Years
Class A Shares	$	711	$	998	$	1,307	$	2,179
Class C Shares	$	328	$	703	$	1,205	$	2,585
Class S Shares	$	169	$	523	$	902	$	1,965
Class I Shares	$	115	$	359	$	622	$	1,375
Class T Shares	$	144	$	446	$	771	$	1,691

1 ï INTECH International Fund

If Shares are not redeemed:	1 Year		3 Years		5 Years		10 Years
Class A Shares	$	711	$	998	$	1,307	$	2,179
Class C Shares	$	228	$	703	$	1,205	$	2,585
Class S Shares	$	169	$	523	$	902	$	1,965
Class I Shares	$	115	$	359	$	622	$	1,375
Class T Shares	$	144	$	446	$	771	$	1,691

Portfolio Turnover: The Fund pays transaction 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 or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 140% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES

The Fund invests primarily in common stocks from the universe of the Morgan Stanley Capital International (“MSCI”) EAFE^® (Europe, Australasia, Far East) Index, utilizing INTECH’s mathematical investment process. The MSCI EAFE^® Index is an MSCI index that is designed to measure the performance of the developed markets of Europe, Australasia, and the Far East. The Fund may also invest in foreign equity and debt securities.

The Fund pursues its investment objective by applying a mathematical investment process to construct an investment portfolio from the universe of common stocks within its named benchmark index. The goal of this process is to build a portfolio of stocks in a more efficient combination than the named benchmark index. The process seeks to capitalize on the natural volatility of the market by searching for stocks within the index that have high relative volatility (providing the potential for excess returns) but that essentially move in opposite directions or have low correlation to each other (providing the potential for lower relative risk). By constructing the portfolio in this manner and periodically rebalancing the portfolio to maintain potentially more efficient weightings, INTECH’s mathematical investment process seeks to create a portfolio that, over time, produces returns in excess of its named benchmark index with risks similar to that of the benchmark index. The rebalancing techniques used by INTECH may result in a higher portfolio turnover compared to a “buy and hold” fund strategy.

PRINCIPAL INVESTMENT RISKS

The biggest risk is that the Fund’s returns will vary, and you could lose money. The Fund is designed for long-term investors seeking an equity portfolio, including common stocks. Common stocks tend to be more volatile than many other investment choices.

Foreign Exposure Risk. The Fund normally has significant exposure to foreign markets as a result of its investments in foreign securities, which can be more volatile than the U.S. markets. As a result, its returns and net asset value may be affected to a large degree by fluctuations in currency exchange rates or political or economic conditions in a particular country. In some foreign markets, there may not be protection against failure by other parties to complete transactions. It may not be possible for the Fund to repatriate capital, dividends, interest, and other income from a particular country or governmental entity. In addition, a market swing in one or more countries or regions where the Fund has invested a significant amount of its assets may have a greater effect on the Fund’s performance than it would in a more geographically diversified portfolio.

Market Risk. The value of the Fund’s portfolio may decrease if the value of an individual company or security, or multiple companies or securities, in the portfolio decreases. Further, regardless of how well individual companies or securities perform, the value of the Fund’s portfolio could also decrease if there are deteriorating economic or market conditions. It is important to understand that the value of your investment may fall, sometimes sharply, in response to changes in the market, and you could lose money.

Investment Process Risk. The proprietary mathematical investment process used by INTECH may not achieve the desired results. On an occasional basis, INTECH considers changes to its mathematical investment process. These changes may result in changes to the portfolio, might not provide the intended results, and may adversely impact the Fund’s performance.

2 ï Janus Investment Fund

Real Estate Risk. The Fund may be affected by risks associated with investments in real estate-related securities. The value of securities of issuers in the real estate and real estate-related industries, including real estate investment trusts, is sensitive to changes in real estate values and rental income, property taxes, interest rates, tax and regulatory requirements, supply and demand, and the management skill and creditworthiness of the issuer. These factors may impact the Fund’s investments in foreign real estate markets differently than U.S. real estate markets.

Portfolio Turnover Risk. Increased portfolio turnover may result in higher costs, which may have a negative effect on the Fund’s performance. In addition, higher portfolio turnover may result in the acceleration of capital gains and the recognition of greater levels of short-term capital gains, which are taxed at ordinary federal income tax rates when distributed to shareholders.

An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

PERFORMANCE INFORMATION

The following information provides some indication of the risks of investing in the Fund by showing how the Fund’s performance has varied over time. Class I Shares, Class A Shares, Class C Shares, and Class S Shares of the Fund commenced operations on July 6, 2009, after the reorganization of each corresponding class of shares of Janus Adviser INTECH Risk-Managed International Fund (“JAD predecessor fund”) into each respective share class of the Fund. Class T Shares of the Fund commenced operations on July 6, 2009.

•  The performance shown for Class I Shares, Class A Shares, Class C Shares, and Class S Shares for periods prior to July 6, 2009, reflects the historical performance of the JAD predecessor fund’s Class I Shares, Class A Shares, Class C Shares, and Class S Shares prior to the reorganization, calculated using the fees and expenses of each respective share class of the JAD predecessor fund, net of any applicable fee and expense limitations or waivers.

•  The performance shown for Class T Shares for periods prior to July 6, 2009, reflects the historical performance of the JAD predecessor fund’s Class I Shares prior to the reorganization, calculated using the fees and expenses of Class T Shares, without the effect of any fee and expense limitations or waivers.

If Class T Shares of the Fund had been available during periods prior to July 6, 2009, the performance shown may have been different. The performance shown for periods following the Fund’s commencement of Class I Shares, Class A Shares, Class C Shares, Class S Shares, and Class T Shares reflects the fees and expenses of each respective share class, net of any applicable fee and expense limitations or waivers.

The bar chart depicts the change in performance from year to year during the periods indicated. The bar chart figures do not include any applicable sales charges that an investor may pay when they buy or sell Class A Shares or Class C Shares of the Fund. If sales charges were included, the returns would be lower. The table compares the Fund’s average annual returns for the periods indicated to a broad-based securities market index. The index is not actively managed and is not available for direct investment. All figures assume reinvestment of dividends and distributions. For certain periods, the Fund’s performance reflects the effect of expense waivers. Without the effect of these expense waivers, the performance shown would have been lower.

The Fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future. Updated performance information is available at janus.com/advisor/mutual-funds or by calling 1-877-335-2687.

3 ï INTECH International Fund

Annual Total Returns for Class I Shares (calendar year-end)
	2008	2009	2010	2011
	−41.75%	25.53%	9.76%	−13.48%
Best Quarter:  Second Quarter 2009  22.50%          Worst Quarter:  Third Quarter 2008  −20.70%

The Fund’s year-to-date return as of the calendar quarter ended September 30, 2012 was 10.64%.

Average Annual Total Returns (periods ended 12/31/11)
	1 Year	Since Inception of Predecessor Fund (5/2/07)
Class I Shares
Return Before Taxes	−13.48%	−6.68%
Return After Taxes on Distributions	−13.63%	−6.83%
Return After Taxes on Distributions and Sale of Fund Shares(1)	−8.62%	−5.43%
MSCI EAFE® Index	−12.14%	−6.74%
(net of foreign withholding taxes) (reflects no deduction for expenses, fees, or taxes, except foreign withholding taxes)
Class A Shares
Return Before Taxes(2)	−18.40%	−7.88%
MSCI EAFE® Index	−12.14%	−6.74%
(net of foreign withholding taxes) (reflects no deduction for expenses, fees, or taxes, except foreign withholding taxes)
Class C Shares
Return Before Taxes(3)	−14.54%	−7.00%
MSCI EAFE® Index	−12.14%	−6.74%
(net of foreign withholding taxes) (reflects no deduction for expenses, fees, or taxes, except foreign withholding taxes)
Class S Shares
Return Before Taxes	−13.42%	−6.78%
MSCI EAFE® Index	−12.14%	−6.74%
(net of foreign withholding taxes) (reflects no deduction for expenses, fees, or taxes, except foreign withholding taxes)
Class T Shares
Return Before Taxes	−13.57%	−8.16%
MSCI EAFE® Index	−12.14%	−6.74%
(net of foreign withholding taxes) (reflects no deduction for expenses, fees, or taxes, except foreign withholding taxes)

(1)	If the Fund incurs a loss, which generates a tax benefit, the Return After Taxes on Distributions and Sale of Fund Shares may exceed the Fund’s other return figures.
(2)	Calculated assuming maximum permitted sales loads.
(3)	The one year return is calculated to include the contingent deferred sales charge.

4 ï Janus Investment Fund

After-tax returns are calculated using distributions for the Fund’s Class I Shares for periods following July 6, 2009; and for the JAD predecessor fund’s Class I Shares for periods prior to July 6, 2009. After-tax returns are calculated using the historically highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on your individual tax situation and may differ from those shown in the preceding table. The after-tax return information shown above does not apply to Fund shares held through a tax-deferred account, such as a 401(k) plan or an IRA.

After-tax returns are only shown for Class I Shares of the Fund. After-tax returns for the other classes of Shares will vary from those shown for Class I Shares due to varying sales charges (as applicable), fees, and expenses among the classes.

MANAGEMENT

Investment Adviser: Janus Capital Management LLC

Investment Subadviser: INTECH Investment Management LLC

Portfolio Management: A team of investment professionals consisting of Adrian Banner, Ph.D. (Chief Executive Officer since November 2012 and Chief Investment Officer since January 2012), Vassilios Papathanakos, Ph.D. (Deputy Chief Investment Officer since November 2012), Joseph W. Runnels, CFA (Vice President of Portfolio Management since March 2003), and Phillip Whitman, Ph.D. (Director of Research since November 2012) works together to implement the mathematical investment process. No one person of the investment team is primarily responsible for implementing the investment strategies of the Fund.

PURCHASE AND SALE OF FUND SHARES

Minimum Investment Requirements*

Class A Shares, Class C Shares**, Class S Shares, and Class T Shares
Non-retirement accounts	$	2,500
Certain tax-deferred accounts or UGMA/UTMA accounts	$	500
Class I Shares
Institutional investors (investing directly with Janus)	$	1,000,000
Through an intermediary institution
• non-retirement accounts	$	2,500
• certain tax-deferred accounts or UGMA/UTMA accounts	$	500

*	Exceptions to these minimums may apply for certain tax-deferred, tax-qualified and retirement plans, and accounts held through certain wrap programs.
**	The maximum purchase in Class C Shares is $500,000 for any single purchase.

Purchases, exchanges, and redemptions can generally be made only through institutional channels, such as financial intermediaries and retirement platforms. Class I Shares may be purchased directly by certain institutional investors. You should contact your financial intermediary or refer to your plan documents for information on how to invest in the Fund. Requests must be received in good order by the Fund or its agents (financial intermediary or plan sponsor, if applicable) prior to the close of the regular trading session of the New York Stock Exchange in order to receive that day’s net asset value. For additional information, refer to “Purchases,” “Exchanges,” and/or “Redemptions” in the Prospectus.

TAX INFORMATION

The Fund’s distributions are taxable, and will be taxed as ordinary income or capital gains, unless you are investing through a tax-deferred arrangement, such as a 401(k) plan or an individual retirement account.

PAYMENTS TO BROKER-DEALERS AND OTHER FINANCIAL INTERMEDIARIES

If you purchase the Fund through a broker-dealer or other financial intermediary (such as a bank), the Fund and its related companies may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment or to recommend one share class over another. Ask your salesperson or visit your financial intermediary’s website for more information.

5 ï INTECH International Fund