Janus Twenty Fund | Class T Shares

FUND SUMMARY Janus Twenty Fund

INVESTMENT OBJECTIVE

Janus Twenty 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.

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses	Janus Twenty Fund Class T Shares Class T
Operating Expenses Column [Text]	Class T
Management Fees (may adjust up or down)	0.64%
Other Expenses	0.30%
Total Annual Fund Operating Expenses	0.94%

EXAMPLE:

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, reinvest all dividends and distributions, and then redeem all of your Shares at the end of each period. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example (USD $)	Expense Example, By Year, Column [Text]	1 Year	3 Years	5 Years	10 Years
Janus Twenty Fund Class T Shares Class T	Class T Shares	96	300	520	1,155

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 56% of the average value of its portfolio.

PRINCIPAL INVESTMENT STRATEGIES

The Fund pursues its investment objective by normally investing primarily in a core group of 20-30 common stocks selected for their growth potential. The Fund may also invest in foreign equity and debt securities, which may include investments in emerging markets.

The portfolio manager applies a “bottom up” approach in choosing investments. In other words, the portfolio manager looks at companies one at a time to determine if a company is an attractive investment opportunity and if it is consistent with the Fund’s investment policies.

The Fund may invest its assets in derivatives, which are instruments that have a value derived from or directly linked to an underlying asset, such as equity securities, bonds, commodities, currencies, interest rates, or market indices, as substitutes for securities in which the Fund invests. The Fund may invest in derivative instruments (by taking long and/or short positions) for different purposes, including hedging (to offset risks associated with an investment, currency exposure, or market conditions) and to earn income and enhance returns. For more information on the Fund’s use of derivatives, refer to the Fund’s shareholder reports and Form N-Q reports, which are filed with the Securities and Exchange Commission.

The Fund may lend portfolio securities on a short-term or long-term basis, in an amount equal to up to 1/3 of its total assets as determined at the time of the loan origination.

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.

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 or if the portfolio manager’s belief about a company’s intrinsic worth is incorrect. 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.

Growth Securities Risk. The Fund invests in companies after assessing their growth potential. Securities of companies perceived to be “growth” companies may be more volatile than other stocks and may involve special risks. If the portfolio manager’s perception of a company’s growth potential is not realized, the securities purchased may not perform as expected, reducing the Fund’s return. In addition, because different types of stocks tend to shift in and out of favor depending on market and economic conditions, “growth” stocks may perform differently from the market as a whole and other types of securities.

Nondiversification Risk. The Fund is classified as nondiversified under the Investment Company Act of 1940, as amended. This gives the Fund’s portfolio manager more flexibility to hold larger positions in a smaller number of securities. As a result, an increase or decrease in the value of a single security held by the Fund may have a greater impact on the Fund’s net asset value and total return.

Foreign Exposure Risk. The Fund may have significant exposure to foreign markets, including emerging markets, 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. The Fund’s investments in emerging market countries may involve risks greater than, or in addition to, the risks of investing in more developed countries.

Derivatives Risk. Derivatives can be highly volatile and involve risks in addition to the risks of the underlying referenced securities. Gains or losses from a derivative can be substantially greater than the derivative’s original cost, and can therefore involve leverage. Derivatives can be less liquid than other types of investments and entail the risk that the counterparty will default on its payment obligations.

Securities Lending Risk. The Fund may seek to earn additional income through lending its securities to certain qualified broker-dealers and institutions. There is the risk that when portfolio securities are lent, the securities may not be returned on a timely basis, and the Fund may experience delays and costs in recovering the security or gaining access to the collateral provided to the Fund to collateralize the loan. If the Fund is unable to recover a security on loan, the Fund may use the collateral to purchase replacement securities in the market. There is a risk that the value of the collateral could decrease below the cost of the replacement security by the time the replacement investment is made, resulting in a loss to the Fund.

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 T Shares (formerly named Class J Shares, the initial share class) of the Fund commenced operations with the Fund’s inception. The performance shown for Class T Shares is calculated using the fees and expenses of Class T Shares in effect during the periods shown, 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 table compares the Fund’s average annual returns for the periods indicated to broad-based securities market indices. The indices are not actively managed and are not available for direct investment. All figures assume reinvestment of dividends and distributions.

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.

Annual Total Returns for Class T Shares (calendar year-end)

Best Quarter: Second Quarter 2009 19.94%          Worst Quarter: Third Quarter 2008 -26.00%

Average Annual Total Returns (periods ended 12/31/11)

Average Annual Total Returns Janus Twenty Fund Class T Shares	Column	Label		Index No Deduction for Fees, Expenses, Taxes [Text]	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes Class T	Class T Shares	Return Before Taxes			(8.19%)	2.11%	4.87%	11.21%	Apr. 30, 1985
Return After Taxes on Distributions Class T	Class T Shares	Return After Taxes on Distributions			(10.30%)	1.62%	4.57%	9.65%	Apr. 30, 1985
Return After Taxes on Distributions and Sale of Fund Shares Class T	Class T Shares	Return After Taxes on Distributions and Sale of Fund Shares	[1]		(2.53%)	1.80%	4.23%	9.32%	Apr. 30, 1985
Russell 1000® Growth Index		Russell 1000® Growth Index		(reflects no deduction for expenses, fees, or taxes)	2.64%	2.50%	2.60%	9.56%	Apr. 30, 1985
S&P 500® Index		S&P 500® Index		(reflects no deduction for expenses, fees, or taxes)	2.11%	(0.25%)	2.92%	10.15%	Apr. 30, 1985

After-tax returns are calculated using distributions for the Fund’s Class T Shares (formerly named Class J Shares, the initial share class). 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.

[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.