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                           PROXY STATEMENT/PROSPECTUS



    The boards of directors of Pioneer Hi-Bred International, Inc. and E. I. du
Pont de Nemours and Company have agreed to a merger in which DuPont will acquire
the remaining approximately 80 percent of Pioneer not presently owned by DuPont.
If the merger is completed, Pioneer shareholders, other than DuPont, will
receive $40 for each Pioneer share they own. Pioneer shareholders may elect to
receive the $40 in cash or in shares of DuPont common stock based on the average
trading price of DuPont common stock over a 10-trading day period ending shortly
before the date of the special meeting of Pioneer shareholders that we will hold
to approve the merger.


    Only 45 percent of the aggregate consideration paid by DuPont will be in the
form of cash and the remaining 55 percent will be in the form of DuPont common
stock. If, in the aggregate, Pioneer shareholders choose to receive cash for
more than 45 percent of the total number of shares of Pioneer common stock
outstanding and not owned by DuPont, those elections will be cut back
proportionately and they will instead receive a portion of the merger
consideration in the form of DuPont common stock. Conversely, if, in the
aggregate, Pioneer shareholders elect to receive shares of DuPont common stock
for more than 55 percent of the total number of shares of Pioneer common stock
outstanding and not owned by DuPont, those elections will be cut back
proportionately and they will instead receive a portion of the merger
consideration in the form of cash.


    We intend that the merger will be tax-free to Pioneer shareholders for that
portion of the consideration they receive in DuPont common stock.



    We cannot complete the merger unless Pioneer shareholders vote to approve
it. Pioneer will hold a special meeting of its shareholders to vote on the
merger agreement. YOUR VOTE IS VERY IMPORTANT.



    This proxy statement/prospectus gives you detailed information about the
meetings and the proposed transactions. We encourage you to read this document
carefully.


    FOR RISKS IN CONNECTION WITH THE MERGER, SEE "RISK FACTORS" BEGINNING ON
PAGE 18.


    I am very enthusiastic about this merger. Bringing the talents and resources
of our two companies more closely together will ensure we can more quickly
deliver potential value to farmers and the broadening agricultural marketplace.
The terms of the merger realize the benefits of that value for our shareholders.
We believe the terms are fair to Pioneer's shareholders other than DuPont. I
join all other members of the Pioneer board of directors in recommending that
you vote in favor of this merger.



                             /s/ CHARLES S. JOHNSON
                               Charles S. Johnson
                Chairman, President and Chief Executive Officer
                      Pioneer Hi-Bred International, Inc.


NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED THE SECURITIES TO BE ISSUED UNDER THIS PROXY
STATEMENT/PROSPECTUS OR DETERMINED IF THIS PROXY STATEMENT/PROSPECTUS IS
ACCURATE OR ADEQUATE. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

PROXY STATEMENT/PROSPECTUS DATED       , 1999, WAS FIRST MAILED TO SHAREHOLDERS
ON OR ABOUT             , 1999.