[Janus letterhead]


May 7, 2009


EDGAR Operations Branch
Securities and Exchange Commission
Division of Investment Management
100 F Street, N.E.
Washington, DC 20549-0505

Re:      JANUS INVESTMENT FUND (the "Registrant")
         1933 Act File No. 2-34393
         1940 Act File No. 811-1879

Dear Sir or Madam:

The Registrant is transmitting today for filing under the Securities Act of
1933, as amended (the "1933 Act"), Pre-Effective Amendment No. 1 to the
registration statement filed on Form N-14 on March 17, 2009 (the "Registration
Statement") relating to the registration of shares of beneficial interest to be
issued in connection with the reorganization of Janus Adviser Small-Mid Growth
Fund (the "Acquired Fund"), a series of Janus Adviser Series, with and into
Janus Triton Fund (the "Acquiring Fund"), a series of the Registrant (the
"Reorganization"). The purpose for filing the Registration Statement is to
include changes made as a result of comments received from the staff of the
Securities and Exchange Commission ("Staff") on an April 16, 2009 telephone
conference call, other immaterial changes and required auditor's consent. The
Registration Statement has been redlined to show changes from the initial
registration statement.

The Registration Statement is also being filed under the Securities Exchange Act
of 1934, as amended. No filing fee is due in connection with this filing.

As noted above, the shares covered by the Registration Statement are to be
issued in connection with the Reorganization. Shares of the Acquiring Fund will
be issued to shareholders of the Acquired Fund in exchange for the transfer of
the Acquired Fund's assets and liabilities to the Acquiring Fund. As discussed
with the Staff on April 16, 2009 and April 28, 2009, pursuant to Rule
17a-8(a)(3) under the Investment Company Act of 1940, as amended, and as
permitted under the Acquired Fund's Trust Instrument, shareholders of the
Acquired Fund are not being requested to approve the Reorganization.

Pursuant to Rule 461(a) under the 1933 Act, the Registrant and Janus
Distributors LLC, the principal underwriter of the Registrant, respectfully
requests that the effectiveness of the Registration Statement be accelerated to
Friday, May 8, 2009 or as soon as practicable.



If you have any questions regarding this filing, please call Rodney DeWalt at
(303) 336-4562 or Stephanie Grauerholz-Lofton at (303) 394-6459.



Sincerely,

Janus Investment Fund

/s/ Stephanie Grauerholz-Lofton

Stephanie Grauerholz-Lofton, Esq
Vice President and Secretary


Janus Distributors LLC

/s/ Michelle Rosenberg

Michelle Rosenberg
Vice President

Enclosures (via EDGAR only)

cc:      Rodney A. DeWalt, Esq.
         Larry Greene, Esq.
         Robin R. Nesbitt, Esq.
         Cindy A. Antonson
         Donna Brungardt