LOOMIS SAYLES FUNDS I:
Loomis Sayles Core Plus Fixed Income Fund
Loomis Sayles Fixed Income Fund
Loomis Sayles Institutional High Income Fund
Loomis Sayles Intermediate Duration Fixed Income Fund
Loomis Sayles Investment Grade Fixed Income Fund
Loomis Sayles U.S. Government Securities Fund
(the Funds)

Supplement dated June 24, 2004 to the Loomis Sayles Funds I
Institutional Funds Prospectus,
dated February 1, 2004, as may be supplemented from time to
time

On June 4, 2004, the Board of Trustees (the Trustees) of
Loomis Sayles Funds approved the use of futures as one of
the principal investment strategies for each of the Funds.
The Trustees also approved the use mortgage dollar rolls as
one of the principal investment strategies for Loomis Sayles
Core Plus Fixed Income Fund, Loomis Sayles Intermediate
Duration Fixed Income Fund, Loomis Sayles Investment Grade
Fixed Income Fund and Loomis Sayles U.S. Government
Securities Fund.

Prospectus Changes

Within the section entitled Risk/Return Summary the
following text is added under Principal Investment
Strategies with respect to Loomis Sayles Core Plus Fixed
Income Fund, Loomis Sayles Intermediate Duration Fixed
Income Fund, Loomis Sayles Investment Grade Fixed Income
Fund and Loomis Sayles U.S. Government Securities Fund.
The Fund may engage in futures transactions.

Within the section entitled Risk/Return Summary the
following text is added under Principal Investment
Strategies with respect to Loomis Sayles Core Plus Fixed
Income Fund, Loomis Sayles Intermediate Duration Fixed
Income Fund, Loomis Sayles Investment Grade Fixed Income
Fund and Loomis Sayles U.S. Government Securities Fund.
The Fund may also invest in mortgage-related securities,
including mortgage dollar rolls.

Within the section entitled Risk/Return Summary the
following is added under Principal Risks with respect
to Loomis Sayles Core Plus Fixed Income Fund and Loomis
Sayles Intermediate Duration Fixed Income Fund.
derivatives risk - the risk that the value of the
Funds derivative investments will fall as a result
of pricing difficulties or lack of correlation with
the underlying investment.

Within the section entitled Risk/Return Summary the
following is added under Principal Risks with respect
to Loomis Sayles Investment Grade Fixed Income Fund and
Loomis Sayles U.S. Government Securities Fund.
derivatives risk - the risk that the value of the
Funds derivative investments will fall as a result of
pricing difficulties or lack of correlation with the
underlying investment.
mortgage-backed securities risk - the risk that the
securities may be prepaid and result in the reinvestment
of the prepaid amounts in securities with lower yields
than the prepaid obligations.  The Fund may also incur
a loss when there is a prepayment of securities that
were purchased at a premium.

Within the section entitled More Information About
The Funds Investments And Risk Considerations the
following text is added.
MORTGAGE DOLLAR ROLLS
The Loomis Sayles Core Plus Fixed Income Fund, Loomis
Sayles Intermediate Duration Fixed Income Fund, Loomis
Sayles Investment Grade Fixed Income Fund and Loomis
Sayles U.S. Government Securities Fund may enter into
mortgage dollar rolls.  A dollar roll involves the sale
of a security by the Funds and its agreement to
repurchase the instrument at a specified time and price,
and may be considered a form of borrowing for some
purposes.  A Fund will segregate assets determined to
be liquid in an amount sufficient to meet its obligations
under the transactions.  A dollar roll involves potential
risks of loss that are different from those related to
the securities underlying the transactions.  A Fund may
be required to purchase securities at a higher price
than may otherwise be available on the open market.
Since the counterparty in the transaction is required
to deliver a similar, but not identical, security to
the Fund, the security that the Funds are required to
buy under the dollar roll may be worth less than an
identical security.  There is no assurance that a Funds
use of the cash that it receives from a dollar roll
will provide a return that exceeds borrowing costs.

M-LSSP08-0604