OppenheimerFunds, Inc.
                   2 World Financial Center, 225 Liberty Street, 11th Floor
                              New York, New York 10281-1008

April 1, 2005

Via Electronic Transmission
---------------------------

Vincent DiStefano, Esq.
U.S. Securities and Exchange Commission
Mail Stop 0-7, Filer Support
6432 General Green Way
Alexandria, Virginia 22312

Re:   Oppenheimer Portfolio Series
      File Nos. 333-121449 and 811-21686

Dear Mr. DiStefano:

      We have reviewed your comments on the registration statement on Form
N-1A for the Oppenheimer Portfolio Series ("Fund") filed with the Commission
on December 20, 2004 relating to four series ("Portfolios"), Conservative
Investor Fund, Moderate Investor Fund, Aggressive Investor Fund and Active
Allocation Fund.  For your convenience, we have included each of your
comments in italics, followed by our response.  The captions used below
correspond to the captions the Fund uses in the registration statement, and
defined terms have the meanings defined therein.

Prospectus
----------

Prospectus Summary

Overview
--------

1. Please define the term "tactical allocation" as it is used in this
   disclosure.

      We have added the following definition of "tactical allocation" to this
      section:

      "Tactical allocation" as used in this Prospectus, refers to a
      strategy that involves adjusting the asset mix to take advantage
      of temporary market conditions that may promise unusual
      opportunities.

2. Please disclose how frequently the Manager will rebalance each Portfolio's
   asset allocations.  Also, please clarify whether, and if so, under what
   circumstances, each Portfolio's percentage allocation to each asset class
   may be changed.

      Each Portfolio's allocation of assets to the underlying funds will be
      monitored daily. The portfolio managers will monitor the market daily
      and seek to maintain the asset allocation balance in response to
      material changes in market or economic conditions.  A rebalancing of
      the percentage of each Portfolio's assts in the in the underlying funds
      will be done at least annually. On page three of the prospectus, we
      state that "In response to changing market or economic conditions, the
      Manager may change the asset class allocations, or the Underlying Funds
      or their target weightings at any time, without prior approval from or
      notice to shareholders." It is anticipated that this will not take
      place frequently and will be in response to significant changes in
      market or economic conditions

About the Portfolios
--------------------

3. For each Portfolio, please disclose the percentage of assets it will
   allocate to each underlying fund and under what circumstances the
   allocation percentages may change.

      The Portfolios do not have target asset allocations with regard to any
      underlying fund. We have not included information regarding the initial
      allocation of assets to the underlying funds since that allocation is
      subject to change daily. We feel that stating a percentage could be
      potentially misleading under the circumstances. We have indicated that
      amount of a Portfolio is invested in the securities of an Underlying
      Fund will affect the extent to which the Portfolio is subject to the
      risks of that Underlying Fund.

4. Please summarize the investment objective and principal strategies and
   risks of each underlying fund in which each Portfolio may invest.

      The investment objective and a summary of the main strategies of each
      underlying fund have been added in a section titled "More Information
      About the Underling Funds" in the prospectus. All of the risks of
      investing in the underlying funds are already included in the
      discussion of the Portfolios.

5. Please summarize the commodities investments the underlying funds may make.

      Only Real Asset Fund invests in commodities. The commodities
      investments of the that fund are summarized in the section "More
      Information About the Underlying Funds.".

6. Please clarify the meaning of the phrase "securities not generally defined
   as equity or fixed income."

      We have modified the disclosure as follows: "other asset classes (that
      may include real estate related securities, commodities, real assets,
      cash or cash equivalents, which are securities not generally defined as
      equity or fixed income)."

7. Please disclose that non-investment grade securities are also known as
   "junk" and carry an increased risk of default.

      We have included the following disclosure regarding non-investment
      grade securities:

      Lower-grade debt securities may be subject to greater market
      fluctuations and greater risks of loss of income and principal than
      investment-grade debt securities. Securities that are (or that have
      fallen) below investment grade include high-yield bonds, commonly
      called "junk bonds," and are exposed to a greater risk that the issuers
      of those securities might default and not meet their debt obligations.
      These risks can reduce the Underlying Fund's share price and the income
      it earns.

8. Please disclose the percentage of assets each underlying fund will invest
   in derivative instruments.

      Where a percentage limitation is applicable to an underlying fund, it
      is included in that fund's registration statement. (The prospectus of
      each underlying fund is available, without charge, by contacting the
      Manager as indicated on the back cover of the Prospectus.) There is no
      target range of indirect investment in derivatives at the Portfolio
      level.

9. Please disclose that shareholders will receive at least 60 days advance
   notice of any changes in a Portfolio's investment objective or principal
   investment strategies.

      We have added the disclosure that "Shareholders will receive at least
      60 days advance notice of changes in the Portfolio's investment
      objective or principal investment strategies."

10.Please provide in this section consistent, objective definitions of the
   terms "small-cap," "mid-cap," and "large-cap."

      We have modified the disclosure to indicate that we are using those
      terms according to the definitions in the underlying funds.

11.Disclosure in this section indicates the Portfolios may invest in
   securities other than shares of the underlying funds.  Please disclose the
   other types of securities in which the Portfolios may invest, and
   summarize the risks of such investments.

      A Portfolio may hold its assets in cash or cash equivalent securities
      in anticipation of investment opportunities or redemptions. We have
      added the following disclosure to the "Overview" section:

      For temporary periods, a Portfolio may hold a portion of its assets in
      cash, money market securities or other similar, liquid investments.
      This will generally occur at times when the Manager is unable to
      immediately invest funds received from purchases of Portfolio shares or
      from redemptions of other investments.

Conservative Investor Portfolio
-------------------------------

12.The disclosure of risks of investing in special situation indicates the
   underlying funds may invest in restructurings.  Are the "restructurings"
   of distressed companies?  If so, how is such a speculative investment
   appropriate for a "conservative" Portfolio?

      One Underlying Fund may, at times, invest in restructurings of
      distressed companies, but such investments will not constitute a
      significant portion of that fund's portfolio or be a significant
      strategy of the fund. Further, that Underlying Fund will be only a
      portion of the Portfolio's international equity fund investments. For
      the Conservative Portfolio, no more than 20% of its assets may be
      invested in equity fund securities of any kind.

13.The disclosure indicates this Portfolio is diversified, yet it invests
   in three underlying funds which are non-diversified.  Please resolve this
   contradiction.

      Although three of the underlying funds in the Conservative Portfolio
      are not diversified funds under the investment company act, those
      underlying funds must meet the diversification requirements for
      registered investment companies under the Internal Revenue Code. Since
      the Portfolio's combined investment in those three funds will not
      constitute more than 10% of the Portfolio's total holdings, the
      Portfolio itself will be diversified.

14.How will the Portfolio monitor and resolve conflicts of interest
   arising from the difference in fees the Manager may receive by virtue of
   investing in one underlying fund instead of another?  Please disclose the
   risk of harm to shareholders.

      We include the following disclosure:

      AFFILIATED PORTFOLIO RISK.  In managing the Portfolio, the Manager will
      have authority to select and substitute Underlying Funds. The Manager
      may be subject to potential conflicts of interest in selecting
      Underlying Funds because the fees paid to it by some Underlying Funds
      are higher than the fees paid by other Underlying Funds. However, the
      Manager is a fiduciary to the Portfolio and is legally obligated to act
      in its best interests when selecting Underlying Funds.

15.Please disclose the risk associated with the simultaneous purchase of a
   security by one underlying fund and sale by another. Does the Manager
   monitor the trading activities of the underlying funds?

       Yes, the Manager monitors trading by the underlying funds in
       connection with its Brokerage Policy as described in the Fund's
       Statement of Additional Information.

Moderate Investor Fund
----------------------

16.The disclosure relating to the risks of using derivative investments
   indicates the Real Asset Fund invests in commodity-linked notes and other
   derivative instruments.  Please explain supplementally how investment in
   these synthetic instruments is consistent with the name of the underlying
   fund.

      These securities and their relationship to that fund's name are
      explained in the Real Asset Fund prospectus as follows:

      Commodity-linked derivative investments provide investors with exposure
      to the investment returns of "real assets" that trade in the
      commodities markets without investing directly in physical commodities.
      "Real assets," as opposed to stocks or bonds, are assets that have
      tangible properties, such as oil, livestock, and agricultural or metal
      products.

17.The disclosure titled "How Risky is the Portfolio Overall?" does not
   answer the question posed by the title.  Please disclose the risk level of
   the Portfolio.

      We have added disclosure to this section of each Portfolio summarizing
      the degree of risk and the suitability considerations.

Active Allocation Fund
----------------------

18.Please provide a complete listing of the types of "other asset classes"
   in which the underlying funds may invest.

      Please see our response to comment #6 above.

19.Please disclose here the investment strategies that constitute
   "tactical allocation."

      Please see our response to comment #1 above.

20.The disclosure indicates the Portfolio will allocate up to 20% of net
   assets to "take advantage of short-term market opportunities."  Will the
   Portfolio market time the underlying funds?

      No. The Portfolio will comply with all of the underlying fund's
      anti-market timing policies.

Shareholder Fees

21.The disclosure preceding the fee table indicates the Portfolio pays
   expenses for asset management, yet the fee table does not contain a
   management fee.  Please correct this inconsistency.  Also, please delete
   "Combined" from the line item "Combined Annual Portfolio Operating
   Expenses" and indicate that the operating expenses are paid from Portfolio
   assets.

      We have revised the caption of the last line of the fee table to remove
      the word "Combined" and to indicate that the expenses shown reflect
      both the expenses of the respective Portfolio and the expenses of the
      underlying funds that are attributable to the Portfolio's investment.

22.   Please disclose the transfer agent's contractual fee rate.

      The transfer agent fee is a per account fee and will therefore vary on
      a percentage basis as account sizes change. Although the Portfolios
      estimate that this fee will not exceed 0.25%, the transfer agent has
      voluntarily agreed to cap this fee at 0.35%.

Can the Portfolio's Investment Objectives and Policies Change?

23.Please move this disclosure to the Summary.

      This disclosure has been moved to the Summary as requested.

The Portfolios' Principal Investment Policies and Risks

24.Why may the Portfolios' asset allocation processes result in additional
   transaction costs if the Portfolios invest solely in the underlying funds?

      This language has been deleted.

25.   Will any of the underlying funds invest in securities in default?  If
   so, please include a description of the attendant risks.  Also, please
   disclose whether an underlying fund will sell or hold non-investment grade
   bonds in the event of default.

      The requested disclosure has been added.

26.The disclosure in this section and elsewhere indicates the underlying
   funds may have relatively high portfolio turnover.  Please disclose the
   consequences of high portfolio turnover, e.g., higher brokerage expenses
                                            ----
   and taxation issues.  Please disclose the underlying funds' estimated
   annual portfolio turnover.

      The risks of high portfolio turnover are indicated in the disclosure.
      The Portfolios will purchase most securities (i.e. shares of the
      underlying funds) directly without any brokerage charges.  It is not
      required that we estimate the annual portfolio turnover rate of the
      underlying funds, but we do indicate that it may be more than 100%.
      The portfolio turnover for each underlying fund's most recently
      completed fiscal year is included in its prospectus.

Special Risk Considerations

27.Please clarify that the securities of government-sponsored entities are
   not backed by the full faith and credit of the U. S. government.

      The requested information has been added.

At What Price Are Shares Sold?

28.Why does the disclosure relating to Net Asset Value not indicate that
   the Portfolios will value their assets using the net asset values of the
   underlying funds?

      We have clarified this disclosure to indicate that the Portfolios
      calculate their net asset value based on the net asset values of the
      Underlying Funds and the Underlying Funds calculate their net asset
      values according to the procedures described.


Statement of Additional Information
-----------------------------------

Investment Restrictions
29.While  the  disclosure   lists  the  investment   restrictions   of  the
   underlying  funds,  it  does  not  list  those  of the  Portfolios.  Please
   disclose the Portfolios' investment restrictions in this section.

      Disclosure regarding the Portfolios' investment restrictions has been
      added to this section.

Disclosure of Portfolio Holdings

30.Please separate the descriptions of public and non-public  disclosure of
   portfolio holdings.

      We have revised the disclosure to indicate which information  relates to
      the public disclosure of the portfolio holdings.

31.Please  explain  supplementally  why  disclosure  of  less  than  entire
   portfolio  holdings to consultants for retirement plans may be made without
   obtaining a  confidentiality  agreement.  Please  disclose the risks to the
   Portfolios   of   disclosing   this   non-public   information   without  a
   confidentiality agreement.

      This disclosure  requires a  confidentiality  agreement.  The disclosure
      has been revised to reflect that information.

Portfolio Proxy Voting

32.Please disclose the  procedures  the  Portfolios  uses when a vote presents a
   conflict  between the interests of the Portfolio  shareholders and those of
   the Adviser,  principal  underwriter or other affiliated persons.  See Item
   12(f) of Form N-1A.

      The requested disclosure has been added.

Approval of Investment Advisory Agreement

33.This  disclosure  does not contain a reasonably  detailed  discussion  of the
   material factors that formed the basis for the board of directors' approval
   of the investment advisory contract. Please include this information in the
   disclosure. See Instruction to Item 12(b) (10) of Form N-1A.

      The disclosure has been revised to comply with this requirement.

      The registrant will be filing a pre-effective amendment reflecting
these changes, but does not expect to submit an exemptive application or
no-action request in connection with this registration statement.

      The Fund requests acceleration of the effective date of the pending
registration statement, and will furnish the proper acknowledgements in that
regard.

      Please direct any questions you may have regarding the filing or this
letter to me at 212-323-5089.

                                          Sincerely,

                                          /s/ Nancy S. Vann

                                          Nancy S. Vann
                                          Vice President and Assistant Counsel
Encl.
cc:  Board IV Board of Trustees
     Carl Algermissen, Esq.
     Ronald M. Feiman, Esq.
     Phillip Gillespie, Esq.
     Dennis Hess
     Scott Huebl
     Michael Keogh
     Gloria LaFond
     Pankaj Naik
     Steve McCandless
     Brian Petersen
     Brian Wixted
     Robert Zack, Esq.