CENTENNIAL GOVERNMENT TRUST
                    Supplement dated December 1, 1997 to the
                        Prospectus dated October 1, 1997

The Prospectus is changed as follows:

The first two  paragraphs in the section  entitled  "Fees and Expenses" on pages
A-1 to A-2 are deleted and replaced with the following paragraphs:

     o Fees and Expenses.  The management fee is payable  monthly to the Manager
under the terms of each Trust's  Agreement and is computed on the average annual
net assets of the  respective  Trust as of the close of business  each day.  The
annual rates  applicable  to Money  Market  Trust are as follows:  0.500% of the
first $250 million of net assets; 0.475% of the next $250 million of net assets;
0.450% of the next $250  million of net assets;  0.425% of the next $250 million
of net assets; 0.400% of the next $250 million of net assets; 0.375% of the next
$250 million of net assets;  0.350% of the next $500 million of net assets;  and
0.325%  of  net  assets  in  excess  of $2  billion.  Furthermore,  the  Manager
guarantees  that the total  expenses of Money  Market  Trust in any fiscal year,
exclusive  of taxes,  interest  and  brokerage  commissions,  and  extraordinary
expenses such as litigation costs,  shall not exceed, and the Manager undertakes
to pay or refund to Money Market Trust any amount by which such  expenses  shall
exceed,  the lesser of (i) 1.5% of the average annual net assets of Money Market
Trust up to $30 million and 1% of its average annual net assets in excess of $30
million; or (ii) 25% of total annual investment income of Money Market Trust.

      The annual rates applicable to Government  Trust are as follows:  0.50% of
the first $250  million of net  assets;  0.475% of the next $250  million of net
assets;  0.45% of the next $250  million of net assets;  0.425% of the next $250
million of net assets; and 0.40% of net assets in excess of $1 billion.

      The annual rates  applicable to Tax Exempt Trust are as follows:  0.50% of
the first $250  million of net  assets;  0.475% of the next $250  million of net
assets;  0.45% of the next $250  million of net assets;  0.425% of the next $250
million of net assets;  0.40% of the next $250 million of net assets;  0.375% of
the next $250  million  of net  assets;  0.35% of the next $500  million  of net
assets and 0.325% of net assets in excess of $2 billion. Furthermore,  under Tax
Exempt  Trust's  Agreement,  when the value of Tax Exempt  Trust's net assets is
less than $1.5  billion,  the annual fee payable to the Manager shall be reduced
by $100,000  based on average net assets  computed daily and paid monthly at the
annual  rates,  but in no event  shall the  annual  fee be less than $0. See the
Statement  of  Additional  Information  for  an  explanation  of  the  Manager's
reimbursement  arrangement  for  the  Trusts  set  forth  in  their  Agreements.
"Investment Management Services" in the

                                                            Continued





Statement of Additional Information contains more complete information about the
Agreements, including a discussion of expense arrangements, and a description of
the exculpation provisions and portfolio transactions.

December 1, 1997                                              PS0170.002








                           CENTENNIAL GOVERNMENT TRUST
                    Supplement dated December 1, 1997 to the
            Statement of Additional Information dated October 1, 1997

The  Statement  of  Additional  Information  is  changed by  deleting  the fifth
paragraph in the section entitled "Investment  Management Services" on pages A-7
and replacing it with the following:

      Independently  of  the  Money  Market  Trust's   Agreement,   the  Manager
voluntarily agreed to waive a portion of the management fee otherwise payable to
it by the Money  Market  Trust  during the period from  December 1, 1991 through
November 21, 1997.  For fiscal year ended June 30, 1995,  June 30, 1996 and June
30,1997, the reimbursements by the Manager to Money Market Trust were $0, $0 and
$4,890,123,  respectively.  Contemporaneously with the amendment of Money Market
Trust's Agreement with the Manager, the Manager withdrew its voluntary waiver on
November 21, 1997.


December 1, 1997                                              PX0170.001