Oppenheimer Portfolio Series Fixed Income Investor Fund
                              (the "Fund")

                                BY-LAWS
                        (dated August 29, 2007)


All terms used herein shall have the same meaning as set forth in the
Declaration of Trust of the Fund unless otherwise defined herein.

                               ARTICLE I

                              SHAREHOLDERS

      Section 1. Shareholder Meetings. Meetings of the Shareholders for
any purpose or purposes may be called by the Chairperson of the Board
of Trustees, if any, or by the President or by the Board of Trustees
and shall be called by the Secretary upon receipt of the request in
writing signed by Shareholders holding not less than one third in
amount of the entire number of Shares issued and outstanding and
entitled to vote thereat. Such request shall state the purpose or
purposes of the proposed meeting. In addition, meetings of the
Shareholders shall be called by the Board of Trustees upon receipt of
the request in writing signed by Shareholders that hold in the
aggregate not less than ten percent in amount of the entire number of
Shares issued and outstanding and entitled to vote thereat, stating
that the purpose of the proposed meeting is the removal of a Trustee.

      Section 2. Place of Meeting. All meetings of the Shareholders
shall be held at the principal office of the Fund or at such other
place as may from time to time be designated by the Board of Trustees
and stated in the notice of meeting.

      Section 3. Notice of Meetings of Shareholders. Consistent with
applicable law, written or printed notice of every meeting of
Shareholders, stating the time and place thereof (and the general
nature of the business proposed to be transacted at any special or
extraordinary meeting), shall be given to each Shareholder entitled to
vote at such meeting by leaving the same with each Shareholder at the
Shareholder's residence or usual place of business or by mailing it,
postage prepaid and addressed to the Shareholder's address as it
appears upon the books of the Fund. Such notice also may be delivered
by such other means, for example electronic delivery, as consistent
with applicable laws.

      No notice of the time, place or purpose of any meeting of
Shareholders need be given to any Shareholder who attends in person or
by proxy or to any Shareholder who, in writing executed and filed with
the records of the meeting, either before or after the holding thereof,
waives such notice.

      Section 4. Record Dates. Consistent with applicable law, the
Board of Trustees may fix, in advance, a record date for the
determination of Shareholders entitled to notice of and to vote at any
meeting of Shareholders and Shareholders entitled to receive any
dividend payment or allotment of rights, as the case may be. Only
Shareholders of record on such date shall be entitled to notice of and
to vote at such meeting or to receive such dividends or rights, as the
case may be.

      Section 5. Access to Shareholder List. The Board of Trustees
shall make available a list of the names and addresses of all
shareholders as recorded on the books of the Fund, upon receipt of the
request in writing signed by not less than ten Shareholders of the Fund
(who have been such for at least six months) holding in the aggregate
the lesser of (i) Shares valued at $25,000 or more at current offering
price (as defined in the Fund's Prospectus), or (ii) one percent in
amount of the entire number of shares of the Fund issued and
outstanding; such request must state that such Shareholders wish to
communicate with other Shareholders with a view to obtaining signatures
to a request for a meeting pursuant to Section 2 of Article I of these
By-Laws and accompanied by a form of communication to the Shareholders.
The Board of Trustees may, in its discretion, satisfy its obligation
under this Section 5 by either making available the Shareholder List to
such Shareholders at the principal offices of the Fund, or at the
offices of the Fund's transfer agent, during regular business hours, or
by mailing a copy of such Shareholders' proposed communication and form
of request, at their expense, to all other Shareholders.

      Section 6.  Quorum, Adjournment of Meetings.  Except as otherwise
required by the Declaration of Trust, the Investment Company Act or
other applicable law, the presence in person or by proxy of one-third
of the Shares entitled to vote shall be a quorum for the transaction of
business at a Shareholders' meeting, provided, however, that if any
action to be taken by the Shareholders of a Series or Class requires an
affirmative vote of a majority, or more than a majority, of the Shares
outstanding and entitled to vote, then with respect to voting on that
particular issue the presence in person or by proxy of the holders of a
majority of the Shares outstanding and entitled to vote at such a
meeting shall constitute a quorum for the transaction of business with
respect to such issue.

      If at any meeting of the Shareholders there shall be less than a
quorum present, the Shareholders present at such meeting may, without
further notice, adjourn the same from time to time until a quorum shall
attend, but no business shall be transacted at any such adjourned
meeting except such as might have been lawfully transacted had the
meeting not been adjourned.

      Section 7.  Adjournment of Meetings When Quorum Present. If a
quorum is present but sufficient votes in favor of one or more
proposals have not been received, any of the persons named as proxies
or attorneys-in-fact may propose one or more adjournments of the
meeting to permit further solicitation of proxies with respect to any
proposal. All such adjournments will require the affirmative vote of a
majority of the shares present in person or by proxy at the session of
the meeting to be adjourned. A vote may be taken on one or more of the
proposals prior to any such adjournment if sufficient votes for its
approval have been received and it is otherwise appropriate.

      Section 8. Voting and Inspectors. Consistent with applicable law,
at all meetings of shareholders, proxies may be given by or on behalf
of a Shareholder orally or in writing or pursuant to any computerized,
telephonic, or mechanical data gathering process.

      All elections of Trustees shall be had by a plurality of the
votes cast and all questions shall be decided by a majority of the
votes cast, in each case at a duly constituted meeting, except as
otherwise provided in the Declaration of Trust or in these By-Laws or
by specific statutory provision superseding the restrictions and
limitations contained in the Declaration of Trust.

      At any election of Trustees, the Board of Trustees prior thereto
may, or, if they have not so acted, the Chairman of the meeting may,
and upon the request of the holders of ten percent (10%) of the Shares
entitled to vote at such election shall, appoint two inspectors of
election who shall first subscribe an oath or affirmation to execute
faithfully the duties of inspectors at such election with strict
impartiality and according to the best of their ability, and shall
after the election make a certificate of the result of the vote taken.
No candidate for the office of Trustee shall be appointed such
Inspector.

      The Chairman of the meeting may cause a vote by ballot to be
taken upon any election or matter, and such vote shall be taken upon
the request of the holders of ten percent (10%) of the Shares entitled
to vote on such election or matter.

      Section 9.  Conduct of Shareholders' Meetings. The meetings of
the Shareholders shall be presided over by the Chairperson of the Board
of Trustees, if any, or if he or she shall not be present, by the
President, or if he shall not be present, by a Vice-President, or if
none of them is present, by a chairperson to be elected at the meeting.
The Secretary of the Fund, if present, shall act as Secretary of such
meetings, or if he or she is not present, an Assistant Secretary shall
so act; if neither the Secretary nor an Assistant Secretary is present,
then the meeting shall elect its secretary.

      Section 10.  Concerning Validity of Proxies, Ballots, Etc. At
every meeting of the Shareholders, all proxies shall be received and
taken in charge of and all ballots shall be received and canvassed by
the secretary of the meeting, who shall decide all questions touching
the qualification of voters, the validity of the proxies, and the
acceptance or rejection of votes, unless inspectors of election shall
have been appointed as provided in Section 7, in which event such
inspectors of election shall decide all such questions.

                               ARTICLE II

                           BOARD OF TRUSTEES

      Section 1.  Number and Tenure of Office. The business and
property of the Fund shall be conducted and managed by a Board of
Trustees consisting of the number of initial Trustees, which number may
be increased or decreased as provided in Section 2 of this Article.
Each Trustee shall, except as otherwise provided herein, hold office
until the meeting of Shareholders of the Fund next succeeding his
election or until his successor is duly elected and qualifies. Trustees
need not be Shareholders.

      Section 2.  Increase or Decrease in Number of Trustees. The Board
of Trustees, by the vote of a majority of the entire Board, may
increase the number of Trustees to a number not exceeding fifteen, and
may elect Trustees to fill the vacancies occurring for any reason,
including vacancies created by any such increase in the number of
Trustees until the next annual meeting or until their successors are
duly elected and qualify; the Board of Trustees, by the vote of a
majority of the entire Board, may likewise decrease the number of
Trustees to a number not less than three but the tenure of office of
any Trustee shall not be affected by any such decrease. In the event
that after the proxy material has been printed for a meeting of
Shareholders at which Trustees are to be elected any one or more
nominees named in such proxy material dies or become incapacitated, the
authorized number of Trustees shall be automatically reduced by the
number of such nominees, unless the Board of Trustees prior to the
meeting shall otherwise determine.

      Section 3.  Removal, Resignation and Retirement. A Trustee at any
time may be removed either with or without cause by resolution duly
adopted by the affirmative votes of the holders of two-thirds of the
outstanding Shares of the Fund, present in person or by proxy at any
meeting of Shareholders at which such vote may be taken, provided that
a quorum is present. Any Trustee at any time may be removed for cause
by resolution duly adopted at any meeting of the Board of Trustees
provided that notice thereof is contained in the notice of such meeting
and that such resolution is adopted by the vote of at least two thirds
of the Trustees whose removal is not proposed. As used herein, "for
cause" shall mean any cause which under Massachusetts law would permit
the removal of a Trustee of a business Fund.

      Any Trustee may resign or retire as Trustee by written instrument
signed by him and delivered to the other Trustees or to any officer of
the Fund, and such resignation or retirement shall take effect upon
such delivery or upon such later date as is specified in such
instrument and shall be effective as to the Fund hereunder.

      Section 4.  Place of Meeting. The Trustees may hold their
meetings, have one or more offices, and keep the books of the Fund
outside Massachusetts, at any office or offices of the Fund or at any
other place as they may from time to time by resolution determine, or,
in the case of meetings, as shall be specified or fixed in the
respective notices or waivers of notice thereof.

      Section 5.  Regular Meetings. Regular meetings of the Board of
Trustees shall be held at such time and on such notice, if any, as the
Trustees may from time to time determine. One such regular meeting
during each fiscal year of the Fund shall be designated an annual
meeting of the Board of Trustees.

      Section 6.  Special Meetings. Special meetings of the Board of
Trustees may be held from time to time upon call of the Chairperson of
the Board of Trustees, if any, the President or two or more of the
Trustees, by oral or written notice duly served on or sent via mail or
electronic delivery to each Trustee not less than one day before such
meeting. No notice need be given to any Trustee who attends in person,
or to any Trustee who in writing executed and filed with the records of
the meeting either before or after the holding thereof waives such
notice. Such notice or waiver of notice need not state the purpose or
purposes of such meeting.

      Section 7.  Quorum. One-third of the Trustees then in office
shall constitute a quorum for the transaction of business, provided
that a quorum shall in no case be less than two Trustees. If at any
meeting of the Board there shall be less than a quorum present (in
person or by open telephone line, to the extent permitted by the
Investment Company Act of 1940 (the "Investment Company Act")), a
majority of those present may adjourn the meeting from time to time
until a quorum shall have been obtained. The act of the majority of the
Trustees present at any meeting at which there is a quorum shall be the
act of the Board, except as may be otherwise specifically provided by
statute, by the Declaration of Trust, by these By-Laws or by any
contract or agreement to which the Fund is a party.

      Section 8.  Executive Committee. The Board of Trustees may, by
the affirmative vote of a majority of the entire Board, elect from the
Trustees an Executive Committee to consist of such number of Trustees
(not less than three) as the Board may from time to time determine. The
Board of Trustees by such affirmative vote shall have power at any time
to change the members of such Committee and may fill vacancies in the
Committee by election from the Trustees. When the Board of Trustees is
not in session, the Executive Committee shall have and may exercise any
or all of the powers of the Board of Trustees in the management of the
business and affairs of the Fund (including the power to authorize the
seal of the Fund to be affixed to all papers which may require it)
except as provided by law or by any contract or agreement to which the
Fund is a party and except the power to increase or decrease the size
of, or fill vacancies on, the Board, to remove or appoint executive
officers or to dissolve or change the permanent membership of the
Executive Committee, and the power to make or amend the By-Laws of the
Fund. The Executive Committee may fix its own rules of procedure, and
may meet when and as provided by such rules or by resolution of the
Board of Trustees, but in every case the presence of a majority shall
be necessary to constitute a quorum. In the absence of any member of
the Executive Committee, the members thereof present at any meeting,
whether or not they constitute a quorum, may appoint a member of the
Board of Trustees to act in the place of such absent member.

      Section 9.  Other Committees. The Board of Trustees, by the
affirmative vote of a majority of the entire Board, may appoint other
committees which shall in each case consist of such number of members
(not less than two) and shall have and may exercise, to the extent
permitted by law, such powers as the Board may determine in the
resolution appointing them. A majority of all members of any such
committee may determine its action, and fix the time and place of its
meetings, unless the Board of Trustees shall otherwise provide. The
Board of Trustees shall have power at any time to change the members
and, to the extent permitted by law, powers of any such committee, to
fill vacancies, and to discharge any such committee.

      Section 10.  Informal Action by and Telephone Meetings of
Trustees and Committees. Any action required or permitted to be taken
at any meeting of the Board of Trustees or any committee thereof may be
taken without a meeting, if a written consent to such action is signed
by all members of the Board, or of such committee, as the case may be.
Trustees or members of the Board of Trustees may participate in a
meeting by means of a conference telephone or similar communications
equipment; such participation shall, except as otherwise required by
the Investment Company Act, have the same effect as presence in person.

      Section 11.  Compensation of Trustees. Trustees shall be entitled
to receive such compensation from the Fund for their services as may
from time to time be voted by the Board of Trustees.

      Section 12.  Dividends. Dividends or distributions payable on the
Shares may, but need not be, declared by specific resolution of the
Board as to each dividend or distribution; in lieu of such specific
resolutions, the Board may, by general resolution, determine the method
of computation thereof, the method of determining the Shareholders to
which they are payable and the methods of determining whether and to
which Shareholders they are to be paid in cash or in additional Shares.


                              ARTICLE III

                                OFFICERS

      Section 1.  Executive Officers. The executive officers of the
Fund may include a Chairperson of the Board of Trustees, and shall
include a President, one or more Vice Presidents (the number thereof to
be determined by the Board of Trustees), a Secretary and a Treasurer.
The Chairman of the Board of Trustees, if any, shall be selected from
among the Trustees. The Board of Trustees or the Executive Committee
may also in its discretion appoint Assistant Secretaries, Assistant
Treasurers, and other officers, agents and employees, who shall have
such authority and perform such duties as the Board or the Executive
Committee may determine. The Board of Trustees may fill any vacancy
which may occur in any office. Any two offices, except those of
President and Vice President, may be held by the same person, but no
officer shall execute, acknowledge or verify any instrument in more
than one capacity, if such instrument is required by law or these
By-Laws to be executed, acknowledged or verified by two or more
officers.

      Section 2.  Term of Office. The term of office of all officers
shall be until their respective successors are chosen and qualify;
however, any officer may be removed from office at any time with or
without cause by the vote of a majority of the entire Board of Trustees.

      Section 3.  Powers and Duties. The officers of the Fund shall
have such powers and duties as generally pertain to their respective
offices, as well as such powers and duties as may from time to time be
conferred by the Board of Trustees or the Executive Committee.

                               ARTICLE IV

                                 SHARES

      Section 1.  Certificates of Shares. Certificates for Shares of
the Fund will not be issued.

      Section 2. Transfer of Shares. Shares shall be transferable on
the books of the Fund by the holder thereof in person or by his duly
authorized attorney or legal representative, upon surrender and
cancellation of certificates, if any, for the same number of Shares,
duly endorsed or accompanied by proper instruments of assignment and
transfer, with such proof of the authenticity of the signature as the
Fund or its agent may reasonably require; in the case of shares not
represented by certificates, the same or similar requirements may be
imposed by the Board of Trustees.

      Section 3. Share Ledgers. The share ledgers of the Fund,
containing the name and address of the Shareholders and the number of
shares, held by them respectively, shall be kept at the principal
offices of the Fund or, if the Fund employs a transfer agent, at the
offices of the transfer agent of the Fund.

                               ARTICLE V

                                  SEAL

      The Board of Trustees shall provide a suitable seal of the Fund,
in such form and bearing such inscriptions as it may determine.

                               ARTICLE VI

                              FISCAL YEAR

      The fiscal year of the Fund shall be fixed by the Board of
Trustees.

                              ARTICLE VII

                          AMENDMENT OF BY-LAWS

      The By-Laws of the Fund may be altered, amended, added to or
repealed by the Shareholders or by majority vote of the entire Board of
Trustees, but any such alteration, amendment, addition or repeal of the
By-Laws by action of the Board of Trustees may be altered or repealed
by the Shareholders.