[Janus Letterhead]



September 18, 2008

VIA EDGAR

Mr. Larry Greene
Division of Investment Management
U.S. Securities and Exchange Commission
100 F Street, N.E.
Washington, DC  20549-0505

Re:   JANUS ADVISER SERIES (the "Registrant")
      1933 Act File No. 333-33978
      1940 Act File No. 811-09885
      Post-Effective Amendment No. 43

Dear Mr. Greene:

On behalf of the Registrant and Janus Adviser International Forty Fund (the
"Fund"), this letter is to respond to your comments made by telephone on May 1,
2008 with respect to the Registrant's Post-Effective Amendment No. 43 filed
pursuant to Rule 485(a) under the Securities Act of 1933, as amended, on March
14, 2008.  The Staff of the Securities and Exchange Commission's (the "Staff")
comments and the Registrant's responses to Staff comments are as follows:

1. COMMENT:  The Staff requested that the Registrant reflect in writing all
   comments and responses and carry over comments, as applicable, to the
   Registrant's other Prospectuses and Statements of Additional Information
   ("SAIs").

   RESPONSE:  The Registrant acknowledges the comment and confirms that it has
   complied.

2. COMMENT:  With respect to the Fund, the Staff notes that in the cases of
   funds with global, international, or worldwide in their names, such funds
   should invest in securities of at least ten countries and have at least 40%
   of their assets invested in securities of foreign countries, excluding the
   U.S.

   RESPONSE:  The Registrant has previously added or revised disclosure as
   appropriate to reflect that such funds invest in several countries.  The
   Registrant believes the investment policies and restrictions of the Fund are
   consistent with formal SEC guidance.

3. COMMENT:  The Staff asked how the Fund's name, "Janus Adviser International
   Forty Fund" and its strategy of investing in a "core group of 30-50 foreign
   equity securities" correlate.

   RESPONSE:  As discussed, the Fund's investment strategy of investing in
   30-50 securities is designed to permit the portfolio manager more flexibility
   than he would have if the Fund was mandated to hold only 40 securities at any
   given time.  The 30-50 "range" allows the portfolio manager to focus on
   maintaining stability within the portfolio rather than forcing the purchase
   or redemption of securities at inopportune times in an effort to maintain the
   strict 40 security strategy.



4. COMMENT:  With respect to the statement, "The Fund will notify you in writing
   at least 60 days before making any change it considers material," the Staff
   commented that Rule 35(d)1 does not contemplate "materiality."

   RESPONSE:  As discussed during our call, the Fund's Board of Trustees has
   adopted a policy of providing shareholders 60-days prior notice regarding a
   change to a fund's investment strategy regardless of whether or not Rule
   35(d)1 applies.

5. COMMENT:  With respect to the statement "If the portfolio manager is unable
   to find such investments, the Fund's uninvested assets may be held in cash or
   similar investments, subject to the Fund's specific investment policies," the
   Staff asked for confirmation that appropriate procedures are in place to
   ensure this is not an open-ended type of arrangement.

   RESPONSE:  The Registrant confirms that appropriate procedures are in place
   to ensure the Fund's investments are in accordance with its investment
   objective and strategy.  In addition, the Registrant has disclosed that in
   the event that a large percentage of Fund assets is held in cash, the Fund
   may not achieve its investment objective.

6. COMMENT:  With respect to disclosure pertaining to the nondiversification
   classification of the Fund, the Staff stated its view that Rule 13a-1 under
   the Investment Company Act of 1940, as amended (the "1940 Act"), is intended
   to apply to nondiversified funds which temporarily become diversified, not
   nondiversified funds which normally operate as diversified funds.  It was the
   Staff's opinion that the disclosure should accurately reflect the Fund's
   subclassification consistent with this view.

   RESPONSE:  The Registrant confirms that the disclosure states that the Fund
   is classified as nondiversified.  Item 2 of Form N-1A instructs that a fund
   that is classified as nondiversified include disclosure that it "may" invest
   a larger portion of its assets in fewer issuers.  The Registrant believes the
   disclosure is consistent with Form N-1A.

7. COMMENT:  With respect to the Fund's disclosure related to Derivatives Risk,
   the Staff asked whether 100% of the Fund's assets could be invested in
   derivatives.

   RESPONSE:  As discussed, the Fund pursues its investment objective by
   investing in foreign equity securities selected for their growth potential.
   Although unlikely, it is possible that the Fund could be fully invested in
   derivatives meeting this criterion.

8. COMMENT:  The Staff asked if the Fund is subject to risks associated with
   subprime mortgage investments.

   RESPONSE:  As discussed, the Registrant does not believe the Fund intends to
   invest to any extent in these types of securities.  However, as the Fund
   gains assets, the Registrant will monitor its investments and update
   disclosure as appropriate.

9. COMMENT:  Under the Fees and Expenses discussion, the Staff questioned a
   reference to the inclusion of estimated annualized expenses associated with
   "networking and/or omnibus account expenses," asking whether or not a
   shareholder would understand what the reference means.

   RESPONSE:  As discussed, additional disclosure pertaining to "networking and
   omnibus" fees is reflected in the Shareholder's Guide within the Prospectus.


10. COMMENT:  The Staff suggested that the footnotes to the Fees and Expenses
    table follow the expense Examples.

    RESPONSE:  The Registrant believes that the most effective presentation of
    the information is reflected in the current disclosure and that it is
    consistent with Item 3 of Form N-1A.  Additionally, General Instruction
    C.1(a) to Form N-1A provides that a fund should use document design
    techniques that promote effective communication which the Registrant
    believes is consistent with its current disclosure.

11. COMMENT:  With respect to the footnotes under the Management Expenses table,
    the Staff asked for confirmation that the font size is consistent with
    guidance provided under Rule 420 of the 1933 Act.

    RESPONSE:  The Registrant confirms that the font size of the information
    contained in the table is compliant with Rule 420.

12. COMMENT:  With respect to disclosure regarding Anti-Money Laundering Program
    requirements under the USA PATRIOT Act, the Staff indicated that the
    disclosure did not state that the Registrant had designated an officer of
    the Fund for purposes of supervising the Registrant's Anti-Money Laundering
    Program.

    RESPONSE:  As discussed during the call, the Trustees of the Registrant
    have designated an officer to supervise the Anti-Money Laundering Program,
    and the Registrant has identified the designated officer in the Trustees and
    Officers table of the SAI.

13. COMMENT:  The Staff noted that disclosure related to the Availability of
    Portfolio Holdings Information referenced "each fund" rather than "the
    fund," leading to potential confusion regarding whether there was more than
    one fund being considered.

    RESPONSE:  The Registrant has updated the disclosure to reference the
    single Fund being offered.

Statement of Additional Information

14. COMMENT:  With respect to disclosure related to the Fund's ability to invest
    in short sales, the Staff stated that additional disclosure may be required
    if expenses related to short sales are significant and result in additional
    dividends or interest.

    RESPONSE:  The Registrant acknowledges the comment and confirms that
    additional disclosure will be added, as appropriate, to the Prospectus Fees
    and Expenses table under "Other Expenses," where expense detail is
    incorporated.

15. COMMENT:  With respect to disclosure regarding the structure and method of
    portfolio manager compensation, the Staff noted that additional disclosure
    may be requested if the benchmark against which performance is measured
    changes during the relevant periods.

    RESPONSE:  The Registrant acknowledges the comment and confirms that it will
    review its disclosure in the event that the Fund's benchmark changes.

16. COMMENT:  The Staff requested that the Registrant provide a Tandy
    representation in a response letter to be filed as correspondence separate
    from the filing.

    RESPONSE:  The Registrant provides its response below.

The Registrant acknowledges responsibility for the adequacy and accuracy of the
disclosure in the filings.  In addition, the Registrant acknowledges that Staff
comments, or changes to disclosure in response to Staff comments in the filings
reviewed by the Staff, do not foreclose the Commission from taking any action
with respect to the filing.

If you have any concerns regarding the above responses, please call me at (303)
336-4562.  Thank you for your assistance in this matter.


Regards,

/s/ Rodney A. DeWalt

Rodney A. DeWalt
Legal Counsel


cc:      Stephanie Grauerholz-Lofton, Esq.
         Cindy Antonson
         Donna Brungardt