Label

Element

Value

Risk/Return:

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Registrant Name

dei_EntityRegistrantName

JANUS INVESTMENT FUND

Prospectus Date

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Jan. 27, 2017

Supplement [Text Block]

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Janus Investment Fund

Janus Global Technology Fund

Supplement dated May 1, 2017

to Currently Effective Prospectuses

The prospectuses for Janus Global Technology Fund (the “Fund”) are amended as follows:

1. Effective May 1, 2017, the following replaces in its entirety the third paragraph found under “Principal Investment Strategies” in the Fund Summary section for the Fund:

The Fund implements this policy by investing primarily in equity securities of U.S. and foreign companies selected for their growth potential. The Fund typically invests at least 40% of its net assets in securities of issuers or companies that are economically tied to different countries throughout the world, excluding the United States. The Fund may, under unusual circumstances, invest in a single country. The Fund may have significant exposure to emerging markets. The Fund may also invest in U.S. and foreign debt securities.

Please retain this Supplement with your records.

Janus Global Technology Fund | Class A, C, S, I, N, T Shares

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

jif_SupplementTextBlock

Janus Investment Fund

Janus Global Technology Fund

Supplement dated May 1, 2017

to Currently Effective Prospectuses

The prospectuses for Janus Global Technology Fund (the “Fund”) are amended as follows:

1. Effective May 1, 2017, the following replaces in its entirety the third paragraph found under “Principal Investment Strategies” in the Fund Summary section for the Fund:

The Fund implements this policy by investing primarily in equity securities of U.S. and foreign companies selected for their growth potential. The Fund typically invests at least 40% of its net assets in securities of issuers or companies that are economically tied to different countries throughout the world, excluding the United States. The Fund may, under unusual circumstances, invest in a single country. The Fund may have significant exposure to emerging markets. The Fund may also invest in U.S. and foreign debt securities.

Please retain this Supplement with your records.

Janus Global Technology Fund | Class D Shares

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

jif_SupplementTextBlock

Janus Investment Fund

Janus Global Technology Fund

Supplement dated May 1, 2017

to Currently Effective Prospectuses

The prospectuses for Janus Global Technology Fund (the “Fund”) are amended as follows:

1. Effective May 1, 2017, the following replaces in its entirety the third paragraph found under “Principal Investment Strategies” in the Fund Summary section for the Fund:

The Fund implements this policy by investing primarily in equity securities of U.S. and foreign companies selected for their growth potential. The Fund typically invests at least 40% of its net assets in securities of issuers or companies that are economically tied to different countries throughout the world, excluding the United States. The Fund may, under unusual circumstances, invest in a single country. The Fund may have significant exposure to emerging markets. The Fund may also invest in U.S. and foreign debt securities.

Please retain this Supplement with your records.