Rule 424(b)(2) Prospectus Supplement
                                                      Registration No. 333-48800


PROSPECTUS SUPPLEMENT No. 4
TO PROSPECTUS DATED August 16, 2001




                                 541,093 Shares

                          BioMarin Pharmaceutical Inc.

                                  Common Stock
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     This Prospectus Supplement supplements information contained in that
certain Prospectus of BioMarin Pharmaceutical Inc. dated August 16, 2001
relating to the potential sale and issuance from time to time of up to 2,500,000
shares of BioMarin common stock. This Prospectus Supplement is not complete
without, and may not be delivered or utilized except in connection with, the
Prospectus, including any amendments or supplements thereto. This Prospectus
Supplement is incorporated by reference into the Prospectus. You should read
this Prospectus Supplement and the accompanying Prospectus carefully before you
invest. Both documents contain information you should consider carefully before
making your investment decision.

     See "Risk Factors" beginning on page 5 of the Prospectus to read about
risks that you should consider before buying shares of our common stock.

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     You should rely only on the information provided or incorporated by
reference in this Prospectus Supplement and the Prospectus. We have not
authorized anyone else to provide you with different information. You should not
assume that the information in this Prospectus Supplement is accurate as of any
date other than the date on the front of this Prospectus Supplement.

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     NEITHER THE SECURITIES EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THE SECURITIES OR PASSED UPON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

                           --------------------------

           The date of this Prospectus Supplement is October 31, 2001





                                TABLE OF CONTENTS


PROSPECTUS SUPPLEMENT

Plan of Distribution.........................................................S-1

PROSPECTUS

Summary........................................................................1

The Offering...................................................................3

Forward Looking Statements.....................................................4

Risk Factors...................................................................5

Use of Proceeds...............................................................16

Plan of Distribution..........................................................17

Legal Matters.................................................................19

Experts.......................................................................19







     The following information supplements the information set forth in the
Prospectus.



                              PLAN OF DISTRIBUTION



     On October 31, 2001, we will issue and sell 541,093 shares of our common
stock to Acqua Wellington North American Equities Fund, Ltd. pursuant to this
prospectus supplement and pursuant to the terms of the common stock purchase
agreement entered into between Acqua Wellington and us on August 15, 2001. The
common stock will be purchased at a negotiated purchase price of $10.1646 per
share. We will pay Reedland Capital Partners, an Institutional Division of
Financial West Group, a fee of $55,000 in consideration of placement agent
services related to this purchase by Acqua Wellington. We will not pay any other
compensation in conjunction with the sale of these shares of our common stock.
See "Plan of Distribution" beginning on page 17 of the prospectus.