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                                                                    EXHIBIT 99.1
 
                             LETTER OF TRANSMITTAL
 
                               OFFER TO EXCHANGE
                          7.10% SENIOR NOTES DUE 2003
                FOR ALL OUTSTANDING 7.10% SENIOR NOTES DUE 2003
                                      AND
                          7.45% SENIOR NOTES DUE 2008
                FOR ALL OUTSTANDING 7.45% SENIOR NOTES DUE 2008
                                       OF
 
                             BECKMAN COULTER, INC.
 
              PURSUANT TO THE PROSPECTUS, DATED APRIL      , 1998
 
 THE EXCHANGE OFFER WILL EXPIRE AT 5:00 P.M., NEW YORK CITY TIME ON           ,
                             1998 UNLESS EXTENDED.
 
           To: The First National Bank of Chicago, The Exchange Agent
 
                        By Registered or Certified Mail:
 
                       The First National Bank of Chicago
                             One North State Street
                                   9th Floor
                            Chicago, Illinois 60602
 
                             By Overnight Delivery:
                       The First National Bank of Chicago
                             One North State Street
                                   9th Floor
                            Chicago, Illinois 60602
                               By Hand Delivery:
                       The First National Bank of Chicago
                             One North State Street
                                   9th Floor
                            Chicago, Illinois 60602
 
                                 By Facsimile:
 
                                 (312) 407-4656
 
                             Confirm by Telephone:
 
                                 (312) 407-2068
 
     DELIVERY OF THIS LETTER OF TRANSMITTAL TO AN ADDRESS OTHER THAN AS SET
FORTH ABOVE OR TRANSMISSION VIA A FACSIMILE NUMBER OTHER THAN TO THE ONE LISTED
ABOVE WILL NOT CONSTITUTE A VALID DELIVERY. THE INSTRUCTIONS ACCOMPANYING THIS
LETTER OF TRANSMITTAL SHOULD BE READ CAREFULLY BEFORE THIS LETTER OF TRANSMITTAL
IS COMPLETED.
 
     The undersigned hereby acknowledges receipt of the Prospectus dated April
     , 1998 (the "Prospectus") of Beckman Coulter, Inc., a Delaware corporation
(the "Company"), and this Letter of Transmittal (the "Letter of Transmittal"),
which together with the Prospectus constitute the Company's offer (the "Exchange
Offer") to exchange (i) its outstanding 7.10% Senior Notes due 2003 (the
"Initial 2003 Notes"), of which an aggregate of $160,000,000 in principal amount
is outstanding, for an equal principal amount of newly issued 7.10% Senior Notes
due 2003 (the "Exchange 2003 Notes"), and (ii) its outstanding 7.45% Senior
Notes due 2008 (the "Initial 2008 Notes" and together with the Initial 2003
Notes, the "Initial Notes"), of which an aggregate of $240,000,000 in principal
amount is outstanding, for an equal principal amount of newly issued 7.45%
Senior Notes due 2008 (the "Exchange 2008 Notes" and together with the Exchange
2003 Notes, the "Exchange Notes"), which Exchange Notes have been registered
under the Securities Act of 1933, as amended (the "Securities Act"), pursuant to
a Registration Statement of which the Prospectus is a part. Capitalized terms
used but not defined herein have the meanings ascribed to them in the
Prospectus.
 
     This Letter of Transmittal is to be completed by a Holder of Initial Notes
if (i) certificates representing the Initial Notes are to be forwarded herewith
or (ii) delivery of Initial Notes is to be made by book-entry transfer to the
account maintained by the Exchange Agent at The Depository Trust Company
("DTC"). Holders whose Initial Notes are not immediately available, or who
cannot deliver their Initial Notes or who
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are unable to complete the procedure for book-entry transfer of their Initial
Notes on a timely basis (a "Book-Entry Confirmation") must tender their Initial
Notes and this Letter of Transmittal in accordance with the guaranteed delivery
procedures set forth under the heading "The Exchange Offer--Guaranteed Delivery
Procedures" in the Prospectus. DELIVERY OF DOCUMENTS TO DTC DOES NOT CONSTITUTE
DELIVERY TO THE EXCHANGE AGENT.
 
     The term "Holder" with respect to the Exchange Offer means any person in
whose name Initial Notes are registered on the books of the Company or any other
person who has obtained a properly completed bond power from the registered
holder. The undersigned has completed, executed and delivered this Letter of
Transmittal to indicate the action the undersigned desires to take with respect
to the Exchange Offer. Holders who wish to tender their Initial Notes must
complete this Letter of Transmittal in its entirety.
 
                                        2
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                 PLEASE READ THIS ENTIRE LETTER OF TRANSMITTAL
                   CAREFULLY BEFORE COMPLETING ANY BOX BELOW
- --------------------------------------------------------------------------------
                                     BOX 1
 

                                                                                        
- ------------------------------------------------------------------------------------------------------------------------
                                                                                AGGREGATE           PRINCIPAL AMOUNT
      NAME(S) AND ADDRESS(ES) OF HOLDER(S) OF                               PRINCIPAL AMOUNT        TENDERED** (MUST
                   INITIAL NOTES                         CERTIFICATE         REPRESENTED BY          BE IN INTEGRAL
             (PLEASE FILL IN, IF BLANK)                  NUMBER(S)*          CERTIFICATE(S)*       MULTIPLE OF $1,000)
- ------------------------------------------------------------------------------------------------------------------------
                                       DESCRIPTION OF INITIAL 2003 NOTES TENDERED
- ------------------------------------------------------------------------------------------------------------------------
 
                                                       --------------------------------------------------------------
 
                                                       --------------------------------------------------------------
 
                                                       --------------------------------------------------------------
                                                            Total
- ------------------------------------------------------------------------------------------------------------------------
                                       DESCRIPTION OF INITIAL 2008 NOTES TENDERED
- ------------------------------------------------------------------------------------------------------------------------
 
                                                       --------------------------------------------------------------
 
                                                       --------------------------------------------------------------
 
                                                       --------------------------------------------------------------
                                                            Total
- ------------------------------------------------------------------------------------------------------------------------
  * Need not be completed by Holders tendering by book-entry transfer (see below).
 ** Unless otherwise indicated in the column labeled "Principal Amount Tendered," any tendering Holder of Initial Notes
 will be deemed to have tendered the entire aggregate principal amount set forth in the column labeled "Aggregate
 Principal Amount Represented by Certificate(s)." If the space provided above is inadequate, list the certificate
 numbers and principal amounts on a separate signed schedule and affix the list to this Letter of Transmittal. The
 minimum permitted tender is $1,000 in principal amount of Initial Notes. All other tenders must be in integral
 multiples of $1,000.
- ------------------------------------------------------------------------------------------------------------------------

 
[ ]  CHECK HERE IF TENDERED INITIAL NOTES ARE ENCLOSED HEREWITH.
 
[ ]  CHECK HERE IF TENDERED INITIAL NOTES ARE BEING DELIVERED BY BOOK-ENTRY
     TRANSFER MADE TO THE ACCOUNT MAINTAINED BY THE EXCHANGE AGENT WITH DTC AND
     COMPLETE THE FOLLOWING (FOR USE BY ELIGIBLE INSTITUTIONS (AS DEFINED
     HEREIN) ONLY):
 
    Name of Tendering Institution
 
    Account Number ________________________ Transaction Code Number
 
[ ]  CHECK HERE IF TENDERED INITIAL NOTES ARE BEING DELIVERED PURSUANT TO A
     NOTICE OF GUARANTEED DELIVERY ENCLOSED HEREWITH AND COMPLETE THE FOLLOWING
     (FOR USE BY ELIGIBLE INSTITUTIONS ONLY):
 
    Name(s) of Registered Holders
 
    Date of Execution of Notice of Guaranteed Delivery
 
    Window Ticket Number (if available)
 
    Name of Institution which Guaranteed Delivery
 
    Account Number (if delivered by book-entry transfer)
 
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                       SIGNATURES MUST BE PROVIDED BELOW
              PLEASE READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY
 
Ladies and Gentlemen:
 
     Upon the terms and subject to the conditions of the Exchange Offer
described in the Prospectus and this Letter of Transmittal, the undersigned
hereby tenders to the Company the principal amount of Initial Notes indicated in
Box 1 above. Subject to, and effective upon, the acceptance for exchange of the
tendered Initial Notes, the undersigned hereby exchanges, assigns, and transfers
to, or upon the order of the Company, all right, title, and interest in, to and
under the tendered Initial Notes. Each DTC participant transmitting by means of
DTC a computer-generated message forming part of a Book-Entry Confirmation, on
behalf of itself and the beneficial owner of the Initial Notes tendered thereby,
acknowledges receipt of the Prospectus and this Letter of Transmittal and agrees
to be bound by the terms and conditions of the Exchange Offer as set forth in
the Prospectus and this Letter of Transmittal.
 
     The undersigned hereby represents and warrants that the undersigned has
full power and authority to tender, exchange, assign, and transfer the tendered
Initial Notes and that the Company will acquire good and unencumbered title
thereto, free and clear of all liens, restrictions, charges, encumbrances, and
adverse claims when the tendered Initial Notes are acquired by the Company as
contemplated herein. The undersigned and each beneficial owner of Initial Notes
tendered by the undersigned will, upon request, execute and deliver any
additional documents reasonably requested by the Company as necessary or
desirable to complete and give effect to the transactions contemplated hereby.
 
     The undersigned hereby irrevocably constitutes and appoints the Exchange
Agent as the true and lawful agent and attorney in fact of the undersigned with
respect to the tendered Initial Notes, with full power of substitution (such
power of attorney being deemed to be an irrevocable power coupled with an
interest), to (i) deliver the tendered Initial Notes to the Company or cause
ownership of the tendered Initial Notes to be transferred to, or upon the order
of, the Company, and deliver all accompanying evidences of transfer and
authenticity to, or upon the order of, the Company upon receipt by the Exchange
Agent, as the undersigned's agent, of the Exchange Notes to which the
undersigned is entitled upon the acceptance by the Company of the tendered
Initial Notes pursuant to the Exchange Offer, and (ii) receive all benefits and
otherwise exercise all rights of beneficial ownership of the tendered Initial
Notes, all in accordance with the terms of the Exchange Offer.
 
     The undersigned also acknowledges that this Exchange Offer is being made by
the Company in reliance on an interpretation by the staff of the Securities and
Exchange Commission (the "Commission"), as set forth in certain no-action
letters to third parties, that the Exchange Notes issued in exchange for the
tendered Initial Notes pursuant to the Exchange Offer may be offered for resale,
resold and otherwise transferred by Holders thereof (other than a broker-dealer,
as set forth below, or any such Holder that is an "affiliate" of the Company
within the meaning of Rule 405 under the Securities Act), without compliance
with the registration and prospectus delivery provisions of the Securities Act,
provided that such Exchange Notes are acquired in the ordinary course of such
Holder's business and such Holders have no arrangement with any person to
participate in the distribution (within the meaning of the Securities Act) of
such Exchange Notes. By tendering, each Holder of Initial Notes represents to
the Company that (i) any Exchange Notes acquired in exchange for Initial Notes
tendered hereby will have been acquired in the ordinary course of business of
the undersigned or such other beneficial owner(s) ("Beneficial Owner(s)")
receiving such Exchange Notes; (ii) neither the undersigned nor any Beneficial
Owner has an arrangement with any person to participate in the distribution of
such Exchange Notes; (iii) the undersigned and each Beneficial Owner acknowledge
and agree that any person who is a broker-dealer registered under the Securities
Exchange Act of 1934, as amended (the "Exchange Act"), or is participating in
the Exchange Offer for the purpose of distributing the Exchange Notes must
comply with the registration and prospectus delivery requirements of the
Securities Act in connection with a secondary resale transaction of the Exchange
Notes or interests therein acquired by such person and cannot rely on the
position of the staff of the Commission set forth in certain no-action letters,
(iv) the undersigned and each Beneficial Owner understand that a secondary
resale transaction described in
 
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clause (iii) above and any resales of Exchange Notes or interests therein
obtained by such Holder in exchange for Initial Notes or interests therein
originally acquired by such Holder directly from the Company should be covered
by an effective registration statement containing the selling security Holder
information required by Item 507 or Item 508, as applicable, of Regulation S-K
of the Commission and (v) neither the undersigned nor any Beneficial Owner is an
"affiliate," as defined in Rule 405 under the Securities Act, of the Company. By
tendering, each Holder of Initial Notes that is a broker-dealer (whether or not
it is also an "affiliate") that will receive Exchange Notes for its own account
pursuant to the Exchange Offer, represents that the Initial Notes to be
exchanged for the Exchange Notes were acquired by it as a result of
market-making activities or other trading activities, and acknowledges that it
will deliver a prospectus meeting the requirements of the Securities Act in
connection with any resale of such Exchange Notes; however, by so acknowledging
and by delivering a prospectus, the Holder will not be deemed to admit that it
is an "underwriter" within the meaning of the Securities Act.
 
     The undersigned understands that tenders of Initial Notes pursuant to the
procedures described under the captions "The Exchange Offer--Procedures for
Tendering" in the Prospectus and in the instructions hereto will constitute a
binding agreement between the undersigned and the Company upon the terms and
subject to the conditions of the Exchange Offer, subject only to withdrawal of
such tenders on the terms set forth in the Prospectus under the caption "The
Exchange Offer--Withdrawal of Tenders." All authority herein conferred or agreed
to be conferred shall survive the death or incapacity of the undersigned and any
Beneficial Owner(s), and every obligation of the undersigned or any Beneficial
Owners hereunder shall be binding upon the heirs, representatives, successors,
and assigns of the undersigned and such Beneficial Owner(s).
 
     If any tendered Initial Notes are not accepted for exchange pursuant to the
Exchange Offer for any reason, certificates for any such unaccepted Initial
Notes will be returned, without expense, to the undersigned at the address shown
below or at such different address as may be indicated herein under "Special
Issuance Instructions" as promptly as practicable after the Expiration Date.
 
     Unless otherwise indicated under "Special Issuance Instructions," the
Company will issue the certificates representing the Exchange Notes issued in
exchange for the Initial Notes accepted for exchange and return any Initial
Notes not tendered or not exchanged, in the name(s) of the undersigned.
Similarly, unless otherwise indicated under "Special Delivery Instructions," the
Company will send the certificates representing the Exchange Notes issued in
exchange for the Initial Notes accepted for exchange and any certificates for
Initial Notes not tendered or not exchanged (and accompanying documents, as
appropriate) to the undersigned at the address shown below the undersigned's
signature(s). In the event that both "Special Issuance Instructions" and
"Special Delivery Instructions" are completed, the Company will issue the
certificates representing the Exchange Notes issued in exchange for the Initial
Notes accepted for exchange in the name(s) of, and return any Initial Notes not
tendered or not exchanged, and send said certificates to the person(s) so
indicated. The undersigned recognizes that the Company has no obligation
pursuant to the "Special Issuance Instructions" and "Special Delivery
Instructions" to transfer any Initial Notes from the name of the registered
Holder(s) hereof if the Company does not accept for exchange any of the tendered
Initial Notes.
 
     Holders of Initial Notes who wish to tender their Initial Notes and (i)
whose Initial Notes are not immediately available, or (ii) who cannot deliver
their Initial Notes, this Letter of Transmittal or any other documents required
hereby to the Exchange Agent prior to the Expiration Date (or who cannot comply
with the book-entry transfer procedure on a timely basis) may tender their
Initial Notes according to the guaranteed delivery procedures set forth in the
Prospectus under the heading "The Exchange Offer--Guaranteed Delivery
Procedures."
 
     IN ORDER TO VALIDLY TENDER INITIAL NOTES FOR EXCHANGE, A HOLDER OF INITIAL
NOTES MUST COMPLETE, EXECUTE AND DELIVER THIS LETTER OF TRANSMITTAL.
 
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- -------------------------------------------------------------------------------------------------------------------
                                                       BOX 2
                                            TENDERING HOLDER SIGNATURE
                                            (SEE INSTRUCTIONS 1 AND 5)
- -------------------------------------------------------------------------------------------------------------------
 
    X                                                         SIGNATURE GUARANTEE
    (Signature(s) of Registered Holder(s) or                  (If required by Instruction 5)
    Authorized Signatory)                                     X
    Date:                                                     (Authorized Signature)
    X
    (Signature(s) of Registered Holder(s) or                  (Name)
    Authorized Signatory)
    Date:                                                     (Title)
    The above lines must be signed by the registered
    Holder(s) of Initial Notes exactly as their name(s)       (Name of Firm)
    appear(s) on the Initial Notes or by person(s)            Date:
    authorized to become registered Holder(s) by a
    properly completed bond power from the registered
    Holder(s), a copy of which must be transmitted with
    this Letter of Transmittal. If Initial Notes to which
    this Letter of Transmittal relate are held of record
    by two or more joint Holders, then all such Holders
    must sign this Letter of Transmittal. If signature is
    by a trustee, executor, administrator, guardian,
    attorney-in-fact, officer, or other person acting in
    a fiduciary or representative capacity, such person
    must (i) set forth his or her full title below and
    (ii) unless waived by the Company, submit evidence
    satisfactory to the Company of such person's
    authority so to act. See Instruction 5.
    Name(s):
    Capacity:
    Street Address:
                     (include zip code)
    Area Code and Telephone Number:
    Tax Identification or Social Security Number:
    Please Complete Substitute Form W-9
- -------------------------------------------------------------------------------------------------------------------

 
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                                     BOX 3
                           (SEE INSTRUCTIONS 5 AND 6)
- --------------------------------------------------------------------------------
 

                                             
SPECIAL ISSUANCE INSTRUCTIONS                   SPECIAL DELIVERY INSTRUCTIONS
     To be completed ONLY (i) if                To be completed ONLY if certificates
certificates for Initial Notes in a             for Initial Notes in a principal amount
principal amount not accepted are to be         not accepted issued in the name of the
issued in the name of someone other             person whose signature appears on the
than the person whose signature appears         face of this Letter of Transmittal are
on the face of this Letter of                   to be sent to someone other than such
Transmittal or (ii) if Initial Notes            person or to such person at an address
tendered by book-entry transfer which           other than that shown in Box 1 entitled
are not accepted are to be returned by          "Description of Initial Notes."
credit to an account maintained at DTC.
 
Name                                                             Name
- ---------------------------------------         ---------------------------------------
(Please Print)                                              (Please Print)
Address                                                         Address
=======================================         =======================================
(Include Zip Code)                                        (Include Zip Code)
- ---------------------------------------         ---------------------------------------
(Tax Identification or Social Security          (Tax Identification or Social Security
No.)                                                             No.)
Credit unaccepted Initial Notes
tendered by book entry transfer to the
DTC account set forth below:
- ---------------------------------------
(DTC Account Number)

 
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                     INSTRUCTIONS TO LETTER OF TRANSMITTAL
 
                    FORMING PART OF THE TERMS AND CONDITIONS
                             OF THE EXCHANGE OFFER
 
     1.   DELIVERY OF THE INITIAL NOTES AND THIS LETTER OF TRANSMITTAL.  This
Letter of Transmittal is to be completed by a Holder of Initial Notes if (i)
certificates representing the Initial Notes are to be forwarded herewith or (ii)
delivery of Initial Notes is to be made by book-entry transfer to the account
maintained by the Exchange Agent at DTC pursuant to the procedures set forth
under the heading "The Exchange Offer--Book-Entry Transfer" in the Prospectus.
Certificates for any physically tendered Initial Notes, or any Book-Entry
Confirmation, as applicable, as well as a properly completed and duly executed
copy of this Letter of Transmittal or facsimile hereof, and any other documents
required by this Letter of Transmittal, must be received by the Exchange Agent
at its address set forth on the cover of this Letter of Transmittal prior to
5:00 p.m., New York City time, on the Expiration Date. The method of delivery of
this Letter of Transmittal and all other required documents to the Exchange
Agent is at the election and risk of the Holder, and the delivery will be deemed
made only when actually received by the Exchange Agent. If delivery is by mail,
it is recommended that the Holder use properly insured, registered mail with
return receipt requested. Instead of delivery by mail, it is recommended that
the Holder use an overnight or hand delivery service. In all cases sufficient
time should be allowed to assure timely delivery. NO LETTER OF TRANSMITTAL OR
INITIAL NOTES SHOULD BE SENT TO THE COMPANY.
 
     2.   GUARANTEED DELIVERY PROCEDURES.  Holders who wish to tender their
Initial Notes and (i) whose Initial Notes are not immediately available or (ii)
who cannot deliver their Initial Notes, the Letter of Transmittal or any other
documents required by the Letter of Transmittal to the Exchange Agent prior to
the Expiration Date must tender their Initial Notes according to the guaranteed
delivery procedures set forth below (if this Letter of Transmittal is being
delivered). Pursuant to such procedures: (i) such tender must be made by or
through a firm which is a member of a registered national securities exchange or
of the National Association of Securities Dealers, Inc., or is a commercial bank
or trust company having an office or correspondent in the United States, or is
otherwise an "eligible guarantor institution" within the meaning of Rule 17Ad-15
under the Exchange Act (an "Eligible Institution"), and the Notice of Guaranteed
Delivery must be signed by the Holder; (ii) prior to the Expiration Date, the
Exchange Agent must have received from the Holder and the Eligible Institution a
properly completed and duly executed Notice of Guaranteed Delivery (by facsimile
transmission, mail or hand delivery) setting forth the name and address of the
Holder of Initial Notes, the certificate number or numbers of the Initial Notes,
and, in each case, the principal amount of the Initial Notes tendered, stating
that the tender is being made thereby and guaranteeing that, within five New
York Stock Exchange ("NYSE") trading days after the Expiration Date, either a
properly completed and duly executed Letter of Transmittal (or a facsimile
thereof), together with the certificate(s) representing the Initial Notes in
proper form for transfer or a Book-Entry Confirmation, as the case may be, and
any other documents required by the Letter of Transmittal, will be deposited by
the Eligible Institution with the Exchange Agent; and (iii) such properly
executed Letter of Transmittal (or facsimile thereof), as well as the
certificate(s) representing all tendered Initial Notes in proper form for
transfer and all other documents required by the Letter of Transmittal are
received by the Exchange Agent within five NYSE trading days after the
Expiration Date. Upon request to the Exchange Agent, a Notice of Guaranteed
Delivery will be sent to Holders who wish to tender their Initial Notes
according to the guaranteed delivery procedures set forth above.
 
     3.   TENDER BY HOLDER.  Only a Holder in whose name Initial Notes are
registered on the books of the registrar (or the legal representative or
attorney-in-fact of such registered Holder) may tender such Initial Notes in the
Exchange Offer. Any beneficial owner of Initial Notes who is not the registered
Holder should arrange with the registered Holder to execute and deliver this
Letter of Transmittal on his or her behalf or must, prior to completing and
executing this Letter of Transmittal and delivering the Initial Notes, either
make appropriate arrangements to register ownership of the Initial Notes in such
beneficial owner's name or obtain a properly completed bond power from the
registered Holder.
 
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     4.   PARTIAL TENDERS.  Tenders of Initial Notes will be accepted only in
integral multiples of $1,000 principal amount. If less than the entire number of
Initial Notes are tendered, the tendering Holder should fill in the number of
Initial Notes tendered in the column labeled "Principal Amount of Initial Notes
Tendered" of Box 1 above. The entire number of Initial Notes delivered to the
Exchange Agent will be deemed to have been tendered unless otherwise indicated.
If the entire number of all Initial Notes indicated in Box 1 above is not
tendered, Initial Notes in a principal amount equal to Initial Notes not
tendered as well as Exchange Notes exchanged for any Initial Notes tendered will
be delivered to the address or account, as applicable, indicated in Box 1,
unless a different address or account, as applicable, is provided in Box 3 of
this Letter of Transmittal.
 
     5.   SIGNATURES ON THE LETTER OF TRANSMITTAL; ENDORSEMENTS; GUARANTEE OF
SIGNATURES.  If this Letter of Transmittal (or facsimile hereof) is signed by
the registered Holder(s) of the Initial Notes tendered hereby, the signature
must correspond with the name(s) as written on the face of the Initial Notes
without alteration, enlargement or any change whatsoever.
 
     If this Letter of Transmittal (or facsimile hereof) is signed by the
registered Holder(s) of Initial Notes tendered and the certificate(s) for
Exchange Notes issued in exchange therefor is to be issued (or any untendered
principal amount of Initial Notes is to be reissued) to the registered Holder,
said Holder need not and should not endorse any certificates representing the
tendered Initial Notes, nor provide a separate bond power. In any other case,
such Holder must either properly endorse certificates representing the Initial
Notes tendered or transmit a properly completed separate bond power with this
Letter of Transmittal, with the signatures on the endorsement or bond power
guaranteed by an Eligible Institution.
 
     If this Letter of Transmittal (or facsimile hereof) is signed by a person
other than the registered Holder(s) of any Initial Notes listed, this Letter of
Transmittal must be accompanied by appropriate bond powers signed as the name of
the registered Holder(s) appear(s) on the face of the Initial Notes without
alteration, enlargement or any change whatsoever.
 
     If this Letter of Transmittal (or facsimile hereof) or any certificates
representing the Initial Notes or bond power are signed by a trustee, executor,
administrator, guardian, attorney-in-fact, officer of a corporation or other
person acting in a fiduciary or representative capacity, such person should so
indicate when signing, and, unless waived by the Company, evidence satisfactory
to the Company of their authority so to act must be submitted with this Letter
of Transmittal.
 
     Signatures on bond powers required by this Instruction 5 must be guaranteed
by an Eligible Institution. Except as otherwise provided below, all signatures
on this Letter of Transmittal must be guaranteed by an Eligible Institution that
is a member of a recognized signature guarantee medallion program (an "Eligible
Program"). Signatures on this Letter of Transmittal need not be guaranteed if
(a) this Letter of Transmittal is signed by the registered Holder(s) of the
Initial Notes tendered herewith and such Holder(s) has not completed the box set
forth herein entitled "Special Issuance Instructions" or the box entitled
"Special Delivery Instructions" or (ii) if such Initial Notes are tendered for
the account of an Eligible Institution. IN ALL OTHER CASES, ALL SIGNATURES MUST
BE GUARANTEED BY AN ELIGIBLE INSTITUTION.
 
     6.   SPECIAL ISSUANCE AND DELIVERY INSTRUCTIONS.  Tendering Holders of
Initial Notes should indicate, in the applicable box or boxes, the name and
address to which Exchange Notes and/or substitute Initial Notes for principal
amounts not tendered or not accepted for exchange are to be issued or sent, if
different from the name and address of the person signing this Letter of
Transmittal. In the case of issuance in a different name, the taxpayer
identification or social security number of the person named must also be
indicated.
 
     7.   TRANSFER TAXES.  The Company will pay all transfer taxes, if any,
applicable to the sale and transfer of Initial Notes to it or its order pursuant
to the Exchange Offer. If, however, a transfer tax is imposed for any reason
other than the transfer and sale of Initial Notes to the Company or its order
pursuant to the Exchange Offer, then the amount of any such transfer taxes
(whether imposed on the registered Holder or on any other person) will be
payable by the tendering Holder. If satisfactory evidence of payment of such
taxes or exemption from taxes therefrom is not submitted with this Letter of
Transmittal, the amount of transfer taxes will be billed directly to such
tendering Holder.
 
                                        9
   10
 
     8.   VALIDITY OF TENDERS.  All questions as to the validity, form,
eligibility (including time of receipt), and acceptance of tendered Initial
Notes will be determined by the Company in its sole discretion, which
determination will be final and binding. The Company reserves the right to
reject any and all Initial Notes not validly tendered or any Initial Notes the
Company's acceptance of which would, in the opinion of the Company or its
counsel, be unlawful. The Company also reserves the right to waive any
conditions of the Exchange Offer or defects or irregularities in tenders of
Initial Notes as to any ineligibility of any Holder who seeks to tender Initial
Notes in the Exchange Offer. The interpretation of the terms and conditions of
the Exchange Offer (including this Letter of Transmittal and the instructions
hereto) by the Company shall be final and binding on all parties. Unless waived,
any defects or irregularities in connection with tenders of Initial Notes must
be cured within such time as the Company shall determine. The Company will use
reasonable efforts to give notification of defects or irregularities with
respect to tenders of Initial Notes, but shall not incur any liability for
failure to give such notification.
 
     9.   WAIVER OF CONDITIONS.  The Company reserves the absolute right to
amend, waive, or modify specified conditions of the Exchange Offer as enumerated
in the Prospectus in the case of any tendered Initial Notes.
 
     10. NO CONDITIONAL TENDER.  No alternative, conditional, irregular, or
contingent tender of Initial Notes or transmittal of this Letter of Transmittal
will be accepted.
 
     11. MUTILATED, LOST, STOLEN OR DESTROYED INITIAL NOTES.  Any tendering
Holder whose Initial Notes have been mutilated, lost, stolen, or destroyed
should contact the Exchange Agent at the address indicated on the cover of this
Letter of Transmittal for further instruction.
 
     12. REQUESTS FOR ASSISTANCE OR ADDITIONAL COPIES.  Questions and requests
for assistance and requests for additional copies of the Prospectus may be
directed to the Exchange Agent at the address on the cover of this Letter of
Transmittal. Holders may also contact their broker, dealer, commercial bank,
trust company, or other nominee for assistance concerning the Exchange Offer.
 
     13. WITHDRAWAL.  Tenders may be withdrawn only pursuant to the limited
withdrawal rights set forth in the Prospectus under the caption "The Exchange
Offer--Withdrawal of Tenders."
 
     IMPORTANT: THIS LETTER OR A FACSIMILE HEREOF (TOGETHER WITH A BOOK-ENTRY
CONFIRMATION AND ANY OTHER REQUIRED DOCUMENTS OR THE NOTICE OF GUARANTEED
DELIVERY, AS APPLICABLE) MUST BE RECEIVED BY THE EXCHANGE AGENT PRIOR TO 5:00
P.M., NEW YORK CITY TIME, ON OR PRIOR TO THE EXPIRATION DATE.
 
                                       10
   11
 
                           IMPORTANT TAX INFORMATION
 
     Under current federal income tax law, a Holder whose tendered Initial Notes
are accepted for exchange may be subject to backup withholding unless the Holder
provides the Exchange Agent with either (i) such Holder's correct taxpayer
identification number ("TIN") on Substitute Form W-9 attached hereto, certifying
that the TIN provided on Substitute Form W-9 is correct (or that such Holder of
Initial Notes is awaiting a TIN) and that (A) the Holder of Initial Notes has
not been notified by the Internal Revenue Service that he or she is subject to
backup withholding as a result of a failure to report interest or dividends or
(B) the Internal Revenue Service has notified the Holder of Initial Notes that
he or she is no longer subject to backup withholding; or (ii) an adequate basis
for exemption from backup withholding. If such Holder is an individual, the TIN
is such Holder's social security number. If the Exchange Agent is not provided
with the correct taxpayer identification number, the Holder may be subject to a
$50 penalty imposed by the Internal Revenue Service. In addition, delivery to
such Holder of the Exchange Notes may be subject to backup withholding.
 
     Certain Holders (including, among others, all corporations and certain
foreign individuals) are not subject to these backup withholding and reporting
requirements. Exempt Holders should indicate their exempt status on Substitute
Form W-9. A foreign individual may qualify as an exempt recipient by submitting
to the Exchange Agent a properly completed Internal Revenue Service Form W-8
(which the Exchange Agent will provide upon request) signed under penalty of
perjury, attesting to the Holder's exempt status. See the enclosed Guidelines
for Certification of Taxpayer Identification Number on Substitute Form W-9 for
additional instructions.
 
     If backup withholding applies, the Company is required to withhold 31% of
any payment made to the Holder or other payee. Backup withholding is not an
additional federal income tax. Rather, the federal income tax liability of
persons subject to backup withholding will be reduced by the amount of tax
withheld. If withholding results in an overpayment of taxes, a refund may be
obtained from the Internal Revenue Service.
 
WHAT NUMBER TO GIVE THE EXCHANGE AGENT
 
     The Holder is required to give the Exchange Agent the social security
number or employer identification number of the record owner of the Initial
Notes. If the Initial Notes are in more than one name or are not in the name of
the actual owner, consult the enclosed Guidelines for Certification of Taxpayer
Identification Number on Substitute Form W-9 for additional guidance on which
number to report.
 
                                       11
   12

                                      
- ---------------------------------------------------------------------------------------------
PAYER'S NAME: THE FIRST NATIONAL BANK OF CHICAGO
- ---------------------------------------------------------------------------------------------
                                            Part 1 -- PLEASE PROVIDE YOUR TIN IN THE BOX
SUBSTITUTE                                  AT RIGHT AND CERTIFY BY SIGNING AND DATING
FORM W-9                                    BELOW
                                        -----------------------------------------------------
 
- -----------------------------------------------------------------------------------------
                                                            TIN
                                                 Social Security Number or
                                               Employer Identification Number
                                        -----------------------------------------------------
 DEPARTMENT OF THE TREASURY
INTERNAL REVENUE SERVICE                    Name
                                            (Please Print)
 PAYOR'S REQUEST FOR TAXPAYER               --------------------------------------------------------
 IDENTIFICATION NUMBER (TIN)                Address
 AND CERTIFICATION                          --------------------------------------------------------
                                            City                    State                    Zip
                                            Code
- --------------------------------------------------------------------------------------------------------
 
                                                    Part 2 --
                                                        Awaiting TIN  [ ]
                                                        Please see below.
- --------------------------------------------------------------------------------------------------------
 
                                         Part 3 -- CERTIFICATION-UNDER PENALTIES OF PERJURY, I CERTIFY THAT:
                                         (1) the number shown on this form is my correct taxpayer identification number (or a TIN
                                             has not been issued to me but I have mailed or delivered an application to receive a
                                             TIN or intend to do so in the near future),
                                         (2) I am not subject to backup withholding either because I have not been notified by the
                                             Internal Revenue Service (the "IRS") that I am subject to backup withholding as a
                                             result of a failure to report all interest or dividends or the IRS has notified me
                                             that I am no longer subject to backup withholding, and
                                         (3) all other information provided on this form is true, correct and complete.
                                         Signature  Date __________________
- --------------------------------------------------------------------------------------------------------

 
 Certificate Instructions -- You must cross out item (2) in Part 3 above if you
 have been notified by the IRS that you are currently subject to backup
 withholding because of underreporting interest or dividends on your tax
 return. However, if after being notified by the IRS that you were subject to
 backup withholding you received another notification from the IRS stating that
 you are no longer subject to backup withholding, do not cross out item (2) in
 Part 3 above.
- --------------------------------------------------------------------------------
               YOU MUST COMPLETE THE FOLLOWING CERTIFICATE IF YOU
                CHECKED THE BOX IN PART 2 OF SUBSTITUTE FORM W-9
 
             CERTIFICATE OF AWAITING TAXPAYER IDENTIFICATION NUMBER
 
I certify under penalties of perjury that a taxpayer identification number has
not been issued to me, and either (a) I have mailed or delivered an application
to receive a taxpayer identification number to the appropriate Internal Revenue
Service Center or Social Security Administration Office or (b) I intend to mail
or deliver an application in the near future. I understand that if I do not
provide a taxpayer identification number within sixty (60) days, 20% of all
reportable payments made to me thereafter will be withheld until I provide a
number.
 

                                                             
- ------------------------------------------------------------    ---------------------------------------------
                         Signature                                                  Date

 
NOTE: FAILURE TO COMPLETE AND RETURN THIS FORM MAY RESULT IN BACKUP WITHHOLDING
      OF 20% OF ANY PAYMENT MADE TO YOU PURSUANT TO THE EXCHANGE OFFER. PLEASE
      REVIEW THE ENCLOSED GUIDELINES FOR CERTIFICATION OF TAXPAYER
      IDENTIFICATION NUMBER ON SUBSTITUTE FORM W-9 FOR ADDITIONAL DETAILS.
 
                                       12
   13
 
            GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION
                         NUMBER ON SUBSTITUTE FORM W-9
 
GUIDELINES FOR DETERMINING THE PROPER IDENTIFICATION NUMBER TO GIVE THE
PAYOR -- Social Security numbers have nine digits separated by two hyphens:
i.e., 000-00-0000. Employer identification numbers have nine digits separated by
one hyphen: i.e., 00-0000000. The table below will help determine the number to
give the payor.



=============================================================
                                         GIVE THE
FOR THIS TYPE OF ACCOUNT:                SOCIAL SECURITY
                                         NUMBER OF --
=============================================================
                                       
 1. An individual's account              The individual
 2. Two or more individuals              The actual owner of
   (joint account)                       the account or, if
                                         combined funds, the
                                         first individual on
                                         the account1

 3. Custodian account of a minor         The minor2
   (Uniform Gift to Minors Act)          

 4. a. The usual revocable savings       The grantor-trustee1
     trust account (grantor is
     also trustee)                       
                                         
   b. So-called trust account that       The actual owner1
     is not a legal or valid             
     trust under State law
 
 5. Sole proprietorship account          The owner3
                              
                             

- ---------------------------------------------------------------------------------
                                         GIVE THE EMPLOYER
 FOR THIS TYPE OF ACCOUNT:               IDENTIFICATION
                                         NUMBER OF --
- ---------------------------------------------------------------------------------
                                      
  6. A valid trust, estate               The legal entity (Do
     or pension trust                    not furnish the
                                         identifying number of
                                         the personal
                                         representative or
                                         trustee unless the legal
                                         entity itself is not
                                         designated in the account
                                         title)4

  7. Corporate account                   The corporation

  8. Association, club,                  The organization
     religious, charitable,
     educational or other                
     tax-exempt organization
                                         
  9. Partnership account                 The partnership

 10. A broker or registered              The broker or nominee
     nominee
                                         
 11. Account with the                    The public entity
     Department of Agriculture
     in the name of a public
     entity (such as a State or
     local government, school
     district or prison) that
     receives agricultural
     program payments
                                                           
=============================================================


1  List first and circle the name of the person whose number you furnish.
 
2  Circle the minor's name and furnish the minor's social security number.
 
3  Show the name of the owner.
 
4  List first and circle the name of the valid trust, estate or pension trust.
 
Note: If no name is circled when there is more than one name, the number will be
      considered to be that of the first name listed.
   14
 
            GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION
                         NUMBER ON SUBSTITUTE FORM W-9
 
                                     PAGE 2
 
OBTAINING A NUMBER
If you don't have a taxpayer identification number or you don't know your
number, obtain Form SS-5, Application for a Social Security Number Card, or Form
SS-4, Application for Employer Identification Number, at the local office of the
Social Security Administration or the Internal Revenue Service and apply for a
number.
PAYEES EXEMPT FROM BACKUP WITHHOLDING
Payees specifically exempt from backup withholding on ALL payments include the
following:
- -   A corporation.
- -   A financial institution.
- -   An organization exempt from tax under section 501(a), or an individual
    retirement plan, or a custodial account under 403(b)(7).
- -   The United States or any agency or instrumentality thereof.
- -   A State, the District of Columbia, a possession of the United States, or any
    subdivision or instrumentality thereof.
- -   A foreign government, a political subdivision of a foreign government, or
    any agency or instrumentality thereof.
- -   An international organization, or any agency or instrumentality thereof.
- -   A dealer in securities or commodities required to register in the U.S. or a
    possession of the U.S.
- -   A real estate investment trust.
- -   A common trust fund operated by a bank under section 584(a).
- -   A trust exempt from tax under Section 644 or described in Section 4947.
- -   An entity registered at all times during the tax year under the Investment
    Company Act of 1940.
- -   A foreign central bank of issue.
- -   Payments made to a middleman known in the investment community as a nominee
    or listed in the most recent publication of the American Society of
    Corporate Secretaries, Inc., Nominee List.
- -   A futures commission merchant registered with the Commodity Futures Trading
    Commission.
Payments of dividends and patronage dividends not generally subject to backup
withholding include the following:
- -   Payments to nonresident aliens subject to withholding under section 1441.
- -   Payments to partnerships not engaged in a trade or business in the U.S. and
    which have at least one nonresident partner.
- -   Payments of patronage dividends where the amount received is not paid in
    money.
- -   Payments made by certain foreign organizations.
Payments of interest not generally subject to backup withholding include the
following:
- -   Payments of interest on obligations issued by individuals.
    Note: You may be subject to backup withholding if this interest is $600 or
    more and is paid in the course of the payer's trade or business and you have
    not provided your correct taxpayer identification number to the payer.
- -   Payments of tax-exempt interest (including exempt interest dividends under
    Section 852).
- -   Payments described in Section 6049(b)(5) to nonresident aliens.
- -   Payments of tax-free covenant bonds under Section 1451.
- -   Payments made by certain foreign organizations.
- -   Mortgage interest paid by you.
Exempt payees described above should file Form W-9 to avoid possible erroneous
backup withholding. FILE THIS FORM WITH THE PAYER, FURNISH YOUR TAXPAYER
IDENTIFICATION NUMBER, WRITE "EXEMPT" ON THE FACE OF THE FORM, AND RETURN IT TO
THE PAYER. IF THE PAYMENTS ARE INTEREST, DIVIDENDS, OR PATRONAGE DIVIDENDS, ALSO
SIGN AND DATE THE FORM.
Certain payments other than interest, dividends, and patronage dividends, that
are not subject to information reporting are also not subject to backup
withholding. For details, see Sections 6041, 6041A(a), 6042, 6044, 6045, 6049,
6050A, and 6050N, and the regulations thereunder.
PRIVACY ACT NOTICE. -- Section 6109 requires most recipients of dividend,
interest or other payments to give taxpayer identification numbers to payers who
must report the payments to the IRS. The IRS uses the numbers for identification
purposes. Payers must be given the numbers whether or not recipients are
required to file tax returns. Payers must generally withhold 20% of certain
taxable payments to a payee who does not furnish a taxpayer identification
number to a payer. Certain penalties may also apply.
PENALTIES
(1) PENALTY FOR FAILURE TO FURNISH TAXPAYER IDENTIFICATION NUMBER. -- If you
fail to furnish your taxpayer identification number to a payer, you are subject
to a penalty of $50 for each such failure unless your failure is due to
reasonable cause and not to willful neglect.
(2) FAILURE TO REPORT CERTAIN PAYMENTS. -- If you fail to include properly on
your tax return certain items reported to the IRS such failure will be treated
as being due to negligence and will be subject to a penalty of 5% on any portion
of an under payment of tax attributable to that failure unless there is clear
and convincing evidence to the contrary.
(3) CIVIL PENALTY FOR FALSE INFORMATION WITH RESPECT TO WITHHOLDING. -- If you
make a false statement with no reasonable basis which results in no imposition
of backup withholding, you are subject to a penalty of $500.
(4) CRIMINAL PENALTY FOR FALSIFYING INFORMATION. -- Willfully falsifying
certifications or affirmations may subject you to criminal penalties including
fines and/or imprisonment.
 
FOR ADDITIONAL INFORMATION CONTACT YOUR TAX
CONSULTANT OR THE INTERNAL REVENUE SERVICE
   15
 
                         NOTICE OF GUARANTEED DELIVERY
                                       OF
                          7.10% SENIOR NOTES DUE 2003
                                      AND
                          7.45% SENIOR NOTES DUE 2008
 
                             BECKMAN COULTER, INC.
 
                PURSUANT TO THE PROSPECTUS DATED APRIL   , 1998
 
THIS FORM, OR ONE SUBSTANTIALLY EQUIVALENT HERETO, MUST BE USED BY ANY HOLDER OF
7.10% SENIOR NOTES DUE 2003 (THE "INITIAL 2003 NOTES") AND ANY HOLDER OF 7.45%
SENIOR NOTES DUE 2008 (THE "INITIAL 2008 NOTES" AND TOGETHER WITH THE INITIAL
2003 NOTES, THE "INITIAL NOTES") OF BECKMAN COULTER, INC., A DELAWARE
CORPORATION (THE "COMPANY"), WHO WISHES TO TENDER HIS OR HER INITIAL NOTES
PURSUANT TO THE COMPANY'S EXCHANGE OFFER, AS DEFINED IN THE PROSPECTUS (THE
"PROSPECTUS"), DATED APRIL      , 1998 AND (i) WHOSE CERTIFICATES REPRESENTING
INITIAL NOTES ARE NOT IMMEDIATELY AVAILABLE, (ii) WHO CANNOT DELIVER HIS OR HER
CERTIFICATES OR ANY OTHER DOCUMENT REQUIRED BY THE LETTER OF TRANSMITTAL ON OR
BEFORE 5:00 P.M., NEW YORK CITY TIME, ON THE EXPIRATION DATE (AS DEFINED IN THE
PROSPECTUS) OR (iii) WHO CANNOT COMPLETE THE PROCEDURE FOR BOOK-ENTRY TRANSFER
ON A TIMELY BASIS. SUCH FORM MAY BE DELIVERED BY FACSIMILE TRANSMISSION, MAIL OR
HAND DELIVERY TO THE EXCHANGE AGENT, SEE "THE EXCHANGE OFFER--GUARANTEED
DELIVERY PROCEDURES" IN THE PROSPECTUS.
 
           To: The First National Bank of Chicago, The Exchange Agent
 

                                         
     By Registered or Certified Mail:                   By Hand Delivery:
    The First National Bank of Chicago          The First National Bank of Chicago
          One North State Street                      One North State Street
                9th Floor                                   9th Floor
         Chicago, Illinois 60602                     Chicago, Illinois 60602
          By Overnight Delivery:                          By Facsimile:
                                                          (312) 407-4656
    The First National Bank of Chicago
          One North State Street                      Confirm by Telephone:
                9th Floor
         Chicago, Illinois 60602                          (312) 407-2068

 
     DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY TO AN ADDRESS OTHER THAN AS
SET FORTH ABOVE OR TRANSMISSION VIA A FACSIMILE NUMBER OTHER THAN TO ONE LISTED
ABOVE WILL NOT CONSTITUTE A VALID DELIVERY.
 
     THIS NOTICE OF GUARANTEED DELIVERY IS NOT TO BE USED TO GUARANTEE
SIGNATURES. IF A SIGNATURE ON A LETTER OF TRANSMITTAL IS REQUIRED TO BE
GUARANTEED BY AN ELIGIBLE INSTITUTION UNDER THE INSTRUCTIONS THERETO, SUCH
SIGNATURE MUST APPEAR IN THE APPLICABLE SPACE PROVIDED IN THE SIGNATURE BOX ON
THE LETTER OF TRANSMITTAL.
   16
 
              PLEASE READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY
 
Ladies and Gentlemen:
 
     The undersigned hereby tenders to the Company, upon the terms and subject
to the conditions of the Exchange Offer as set forth in the Prospectus and the
related Letter of Transmittal, receipt of which is hereby acknowledged, the
principal amount of Initial 2003 Notes and Initial 2008 Notes specified below
pursuant to the guaranteed delivery procedures set forth under the caption "The
Exchange Offer--Guaranteed Delivery Procedures" in the Prospectus. The
undersigned hereby tenders the Initial Notes listed below:
 

                                                       
- -------------------------------------------------------------------------------------------------------------------
         INITIAL 2003 NOTES CERTIFICATE NUMBERS
                     (IF AVAILABLE)                                       PRINCIPAL AMOUNT TENDERED
- -------------------------------------------------------------------------------------------------------------------
 
- -------------------------------------------------------------------------------------------------------------------
 
- -------------------------------------------------------------------------------------------------------------------
         INITIAL 2008 NOTES CERTIFICATE NUMBERS
                     (IF AVAILABLE)                                       PRINCIPAL AMOUNT TENDERED
- -------------------------------------------------------------------------------------------------------------------
 
- -------------------------------------------------------------------------------------------------------------------
 
- -------------------------------------------------------------------------------------------------------------------
 
 If Initial Notes will be tendered by           SIGN HERE
 book-entry transfer:                           --------------------------------------------
                                                Signature(s)
 Name of Tendering Institution:                --------------------------------------------
- --------------------------------------------    Name(s) (Please Print)
                                               --------------------------------------------
 Account No.                                   --------------------------------------------
 at The Depository Trust Company                Address
                                               --------------------------------------------
                                                Zip Code
                                               --------------------------------------------
                                                Area Code and Telephone No.
                                                Date:
 
- ---------------------------------------------------------------------------------------------

 
                                        2
   17
 
                                   GUARANTEE
                    (NOT TO BE USED FOR SIGNATURE GUARANTEE)
 
The undersigned, a firm that is a member of a registered national securities
exchange or of the National Association of Securities Dealers, Inc., or is a
commercial bank or trust company having an office or correspondent in the United
States, or is otherwise an "eligible guarantor institution" within the meaning
of Rule 17Ad-15 under the Securities Exchange Act of 1934, as amended (the
"Exchange Act"), hereby (a) represents that the above named person(s) "own(s)"
the Initial Notes tendered hereby within the meaning of Rule 14e-4 under the
Exchange Act, (b) represents that such tender of Initial Notes complies with
Rule 14e-4 under the Exchange Act and (c) guarantees that delivery to the
Exchange Agent of the certificate(s) representing the Initial Notes in proper
form for transfer or a Book-Entry Confirmation, pursuant to the procedures for
book-entry transfer set forth in the Prospectus, and delivery of a properly
completed and duly executed Letter of Transmittal (or manually signed facsimile
thereof) with any required signatures and any other documents required by the
Letter of Transmittal, will be received by the Exchange Agent by 5:00 p.m., New
York City time, on the third New York Stock Exchange trading day after the
Expiration Date.
 
                                            SIGN HERE
 
                                            ------------------------------------
                                            Name of Firm
 
                                            ------------------------------------
                                            Authorized Signature
 
                                            ------------------------------------
                                            Name (please print)
 
                                            ------------------------------------
                                            Title
 
                                            ------------------------------------
                                            Address
 
                                            ------------------------------------
                                            Zip Code
 
                                            ------------------------------------
                                            Area Code and Telephone No.
 
                                            Date:
 
DO NOT SEND INITIAL NOTES WITH THIS FORM. ACTUAL SURRENDER OF INITIAL NOTES MUST
BE MADE PURSUANT TO, AND BE ACCOMPANIED BY, A COPY OF THE PREVIOUSLY EXECUTED
LETTER OF TRANSMITTAL.
 
                                        3
   18
 
                                  INSTRUCTIONS
 
     1.  DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY.  A properly completed
and duly executed copy of this Notice of Guaranteed Delivery and any other
documents required by this Notice of Guaranteed Delivery must be received by the
Exchange Agent at its address set forth on the cover hereof prior to the
Expiration Date. The method of delivery of this Notice of Guaranteed Delivery
and all other required documents to the Exchange Agent is at the election and
risk of the Holder, and the delivery will be deemed made only when actually
received by the Exchange Agent. If delivery is by mail, it is recommended that
the Holder use properly insured, registered mail with return receipt requested.
Instead of delivery by mail, it is recommended that the Holder use an overnight
or hand delivery service. In all cases sufficient time should be allowed to
assure timely delivery. For a full description of the guaranteed delivery
procedures, see the Prospectus under the caption "The Exchange Offer--Guaranteed
Delivery Procedures." NO NOTICE OF GUARANTEED DELIVERY SHOULD BE SENT TO THE
COMPANY.
 
     2.  SIGNATURE ON THIS NOTICE OF GUARANTEED DELIVERY; GUARANTEE OF
SIGNATURES.  If this Notice of Guaranteed Delivery is signed by the registered
Holder(s) of the Initial Notes referred to herein, the signature must correspond
with the name(s) as written on the face of the Initial Notes without alteration,
enlargement or any change whatsoever.
 
     If this Notice of Guaranteed Delivery is signed by a person other than the
registered Holder(s) of any Initial Notes listed, this Notice of Guaranteed
Delivery must be accompanied by appropriate bond powers signed as the name of
the registered Holder(s) appear(s) on the face of the Initial Notes without
alteration, enlargement or any change whatsoever.
 
     If this Notice of Guaranteed Delivery is signed by a trustee, executor,
administrator, guardian, attorney-in-fact, officer of a corporation or other
person acting in a fiduciary or representative capacity, such person should so
indicate when signing, and, unless waived by the Company, evidence satisfactory
to the Company of their authority so to act must be submitted with this Notice
of Guaranteed Delivery.
 
     3.  REQUESTS FOR ASSISTANCE OR ADDITIONAL COPIES.  Questions and requests
for assistance and requests for additional copies of the Prospectus may be
directed to the Exchange Agent at the address specified in the Prospectus.
Holders also may contact their broker, dealer, commercial bank, trust company,
or other nominee for assistance concerning the Exchange Offer.
 
                                        4
   19
 
                               OFFER TO EXCHANGE
                          7.10% SENIOR NOTES DUE 2003
                FOR ALL OUTSTANDING 7.10% SENIOR NOTES DUE 2003
                                      AND
                          7.45% SENIOR NOTES DUE 2008
                FOR ALL OUTSTANDING 7.45% SENIOR NOTES DUE 2008
                                       OF
 
                             BECKMAN COULTER, INC.
 
To Securities Dealers, Commercial Banks,
  Trust Companies and Other Nominees:
 
     We are enclosing herewith the materials listed below relating to the offer
(the "Exchange Offer") by Beckman Coulter, Inc. (the "Company") to exchange (i)
its outstanding 7.10% Senior Notes due 2003 (the "Initial 2003 Notes"), of which
an aggregate of $160,000,000 in principal amount is outstanding, for an equal
principal amount of newly issued 7.10% Senior Notes due 2003 (the "Exchange 2003
Notes"), and (ii) its outstanding 7.45% Senior Notes due 2008 (the "Initial 2008
Notes" and together with the Initial 2003 Notes, the "Initial Notes"), of which
an aggregate of $240,000,000 in principal amount is outstanding, for an equal
principal amount of newly issued 7.45% Senior Notes due 2008 (the "Exchange 2008
Notes" and together with the Exchange 2003 Notes, the "Exchange Notes"), which
Exchange Notes have been registered under the Securities Act of 1933, as
amended, upon the terms and subject to the conditions set forth in the
Prospectus, dated April   , 1998 (the "Prospectus"), and the related Letter of
Transmittal (the "Letter of Transmittal"). Capitalized terms used but not
defined herein have the meanings ascribed to them in the Prospectus.
 
     Enclosed herewith are copies of the following documents:
 
     1.    The Prospectus;
 
     2.    Letter of Transmittal;
 
     3.    Notice of Guaranteed Delivery;
 
     4.    Letter which may be sent to your clients for whose account you hold
           Initial Notes registered in your name or in the name of your nominee,
           with space provided for obtaining such client's instruction with
           regard to the Exchange Offer;
 
     5.    Guidelines for Certification of Taxpayer Identification Number on
           Substitute Form W-9.
 
     WE URGE YOU TO CONTACT YOUR CLIENTS PROMPTLY. PLEASE NOTE THAT THE EXCHANGE
OFFER WILL EXPIRE AT 5:00 P.M., NEW YORK CITY TIME, ON           , 1998, UNLESS
EXTENDED (THE "EXPIRATION DATE").
 
     To tender Initial Notes, certificates for Initial Notes or a Book-Entry
Confirmation, a duly executed and properly completed Letter of Transmittal or a
facsimile thereof and any other required documents must be received by the
Exchange Agent as provided in the Prospectus and the Letter of Transmittal.
 
     The Company will not pay any fee or commission to any broker or dealer or
to any other persons (other than the Exchange Agent) in connection with the
solicitation of tenders of Initial Notes pursuant to the Exchange Offer. The
Company will pay or cause to be paid any transfer taxes payable on the transfer
of Initial Notes to it, except as otherwise provided in Instruction 7 of the
enclosed Letter of Transmittal.
 
     Additional copies of the enclosed material may be obtained from The First
National Bank of Chicago, One North State Street, 9th Floor, Chicago, Illinois
60602, (312) 407-2068.
 
     NOTHING CONTAINED HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL CONSTITUTE YOU
AS THE AGENT OF THE COMPANY OR THE EXCHANGE AGENT OR AUTHORIZE YOU TO USE ANY
DOCUMENT OR MAKE ANY STATEMENT ON THEIR BEHALF IN CONNECTION WITH THE EXCHANGE
OFFER OTHER THAN THE DOCUMENTS ENCLOSED HEREWITH AND THE STATEMENTS CONTAINED
THEREIN.
   20
 
                               OFFER TO EXCHANGE
                          7.10% SENIOR NOTES DUE 2003
                FOR ALL OUTSTANDING 7.10% SENIOR NOTES DUE 2003
                                      AND
                          7.45% SENIOR NOTES DUE 2008
                FOR ALL OUTSTANDING 7.45% SENIOR NOTES DUE 2008
                                       OF
 
                             BECKMAN COULTER, INC.
 
To Our Clients:
 
     We are enclosing herewith a Prospectus, dated April   , 1998 (the
"Prospectus") and a related Letter of Transmittal (the "Letter of Transmittal")
relating to the offer (the "Exchange Offer") by Beckman Coulter, Inc. (the
"Company") to exchange (i) its outstanding 7.10% Senior Notes due 2003 (the
"Initial 2003 Notes"), of which an aggregate of $160,000,000 in principal amount
is outstanding, for an equal principal amount of newly issued 7.10% Senior Notes
due 2003 (the "Exchange 2003 Notes"), and (ii) its outstanding 7.45% Senior
Notes due 2008 (the "Initial 2008 Notes" and together with the Initial 2003
Notes, the "Initial Notes"), of which an aggregate of $240,000,000 in principal
amount is outstanding, for an equal principal amount of newly issued 7.45%
Senior Notes due 2008 (the "Exchange 2008 Notes" and together with the Exchange
2003 Notes, the "Exchange Notes"), which Exchange Notes have been registered
under the Securities Act of 1933, as amended, upon the terms and subject to the
conditions set forth in the Prospectus and the Letter of Transmittal.
Capitalized terms used but not defined herein have the meanings ascribed to them
in the Prospectus.
 
     These materials are being forwarded to you as the beneficial owner of
Initial Notes carried by us for your account or benefit but not registered in
your name. A tender of any Initial Notes may be made only by us as the
registered Holder and pursuant to your instructions. Therefore, the Company
urges beneficial owners of Initial Notes registered in the name of a broker,
dealer, commercial bank, trust company or other nominee to contact such
registered Holder promptly if they wish to tender Initial Notes in the Exchange
Offer.
 
     Accordingly, we request instructions as to whether you wish us to tender
any or all Initial Notes, pursuant to the terms and conditions set forth in the
Prospectus and Letter of Transmittal. We urge you to read carefully the
Prospectus and Letter of Transmittal before instructing us to tender your
Initial Notes.
 
     YOUR INSTRUCTIONS TO US SHOULD BE FORWARDED AS PROMPTLY AS POSSIBLE IN
ORDER TO PERMIT US TO TENDER INITIAL NOTES ON YOUR BEHALF IN ACCORDANCE WITH THE
PROVISIONS OF THE EXCHANGE OFFER. THE EXCHANGE OFFER WILL EXPIRE AT 5:00 P.M.,
NEW YORK CITY TIME, ON          , 1998, UNLESS EXTENDED.
 
     If you wish to have us tender any or all of your Initial Notes held by us
for your account or benefit, please so instruct us by completing, executing and
returning to us the instruction form that appears below. The accompanying Letter
of Transmittal is furnished to you for informational purposes only and may not
be used by you to tender Initial Notes held by us and registered in our name for
your account or benefit.
   21
 
                                  INSTRUCTIONS
 
     The undersigned hereby acknowledges receipt of your letter and enclosed
materials referred to therein relating to the Exchange Offer of Beckman
Instruments, Inc.
 
     THIS WILL INSTRUCT YOU TO TENDER THE PRINCIPAL AMOUNT OF INITIAL NOTES
INDICATED BELOW HELD BY YOU FOR THE ACCOUNT OR BENEFIT OF THE UNDERSIGNED,
PURSUANT TO THE TERMS OF AND CONDITIONS SET FORTH IN THE PROSPECTUS AND THE
LETTER OF TRANSMITTAL.
 
  [ ] Please TENDER my Initial Notes held by you for the account or benefit of
      the undersigned. I have identified on a signed schedule attached hereto
      the principal amount of Initial Notes to be tendered if I wish to tender
      less than all of my Initial Notes.
 
  [ ] Please DO NOT TENDER any Initial Notes held by you for the account of the
      undersigned.
 

                                
Date:
 
                                   -----------------------------------------------------
                                                       Signature(s):
 
                                   -----------------------------------------------------
 
                                   -----------------------------------------------------
                                                  Name(s) (please print)

 
     Unless a specific contrary instruction is given in a signed Schedule
attached hereto, your signature(s) hereon shall constitute an instruction to us
to tender all of your Initial Notes.