PROSPECTUS SUPPLEMENT NO. 6
                     (TO PROSPECTUS DATED JANUARY 10, 2001)

                                  87,308 SHARES

                            IGEN INTERNATIONAL, INC.

                                  COMMON STOCK

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

       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.

        INVESTING IN OUR COMMON STOCK INVOLVES CERTAIN RISKS. SEE "RISK
                 FACTORS" BEGINNING ON PAGE 6 OF THE PROSPECTUS.

                              PLAN OF DISTRIBUTION

       We are offering  87,308  shares of our common  stock to Acqua  Wellington
North American Equities Fund, Ltd. pursuant to this prospectus  supplement.  The
common  stock will be  purchased  at an average  purchase  price of $26.6889 per
share. We will not pay any other  compensation  in conjunction  with the sale of
our common stock.

       Acqua  Wellington  and  its  pledgees,   donees,  transferees  and  other
subsequent owners, may offer their shares at various times in one or more of the
following transactions:

       -   in the over-the-counter market; or

       -   in privately negotiated transactions

at  prevailing  market  prices at the time of sale,  at prices  related to those
prevailing market prices, at negotiated or at fixed prices.

       The  transactions  in the  shares may be  effected  by one or more of the
following methods:

       -   ordinary brokerage  transactions and transactions in which the broker
           solicits purchasers;

       -   purchases by a  broker or dealer as principal, and the resale by that
           broker or dealer for its  account  under this  prospectus,  including
           resale to another broker or dealer;

       -   block trades  in which  the broker or dealer will attempt to sell the
           shares as agent but may position and resell a portion of the block as
           principal in order to facilitate the transaction; or

       -   negotiated transactions  between selling  stockholders and purchasers
           without a broker or dealer.

       Acqua Wellington is an "underwriter" within the meaning of the Securities
Act in  connection  with its sale of the shares  purchased  from us described in
this prospectus supplement. Broker-dealers or other persons acting on the behalf
of parties that participate in the distribution of the shares may also be deemed
to be underwriters. Any commissions or profits they receive on the resale of the
shares may be deemed to be  underwriting  discounts  and  commissions  under the
Securities Act.

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       During  the time Acqua  Wellington  is  engaged  in  distributing  shares
covered by this  prospectus,  Acqua Wellington will comply with the requirements
of the  Securities  Act and Rule 10b-5 and  Regulation M under the Exchange Act.
Under those rules and regulations, they:

       -   may not  engage in any  stabilization activity in connection with our
           securities;

       -   must furnish  each broker which offers shares of common stock covered
           by this prospectus with the number of copies of this prospectus which
           are required by each broker; and

       -   may  not  bid  for  or purchase  any of our  securities or attempt to
           induce any person to  purchase  any of our  securities  other than as
           permitted under the Exchange Act.

       In connection with Acqua  Wellington's  purchase and potential  resale of
the shares covered by this prospectus supplement, we will agree to indemnify and
hold harmless Acqua  Wellington  and each person who controls  Acqua  Wellington
against certain  liabilities,  including  liabilities  under the Securities Act,
which may be based upon,  among other  things,  any untrue  statement or alleged
untrue  statement of a material  fact or any  omission or alleged  omission of a
material  fact,  unless made or omitted in  reliance  upon  written  information
provided to us by Acqua Wellington.

       We have agreed to bear the expenses  incident to the  registration of the
shares,  other than  selling  discounts  and  commissions.  These  expenses  are
estimated to be $2,000.

                                USE OF PROCEEDS

       We will use the proceeds of this offering as described in the prospectus.
See "Use of Proceeds" beginning on page 23 of the prospectus.

         THE DATE OF THIS PROSPECTUS SUPPLEMENT IS SEPTEMBER 26, 2001


                                      S-2


                      WHERE YOU CAN FIND MORE INFORMATION

       The SEC allows us to "incorporate by reference"  information that we file
with them,  which means that we can  disclose  important  information  to you by
referring you to those documents.  The information  incorporated by reference is
an important part of this prospectus supplement and the accompanying prospectus.
We incorporate the documents listed on page 22 of the prospectus.

                          MARKET FOR OUR COMMON STOCK

         On September 25, 2001, the last reported sale price of our common stock
on the Nasdaq National  Market was $23.69 per share.  Our common stock is listed
on the Nasdaq  National  Market  under the symbol  "IGEN." The common stock sold
under this  prospectus  supplement  will be listed on the Nasdaq National Market
after we notify the Nasdaq National Market that the shares have been issued.

         As of September  25,  2001,  we had  19,507,793  shares of common stock
outstanding.

                                    GENERAL

       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 these documents.

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 OR PROSPECTUS SUPPLEMENT.  ANY REPRESENTATION TO THE
CONTRARY IS A CRIMINAL OFFENSE.


                                      S-3


                               TABLE OF CONTENTS

PROSPECTUS SUPPLEMENT                                                       PAGE
           Plan of Distribution                                              S-1
           Use of Proceeds                                                   S-2
           Where You Can Find More Information                               S-3
           Market for Our Common Stock                                       S-3
           General                                                           S-3


PROSPECTUS
           Prospectus Summary                                                1
           The Offering                                                      2
           Risk Factors                                                      3
           Forward-Looking Statements                                        11
           Where You Can Find More Information                               11
           Incorporation of Documents by Reference                           12
           Use of Proceeds                                                   13
           Plan of Distribution                                              14
           Legal Matters                                                     14
           Experts                                                           14
           Indemnification                                                   15