EXHIBIT 99.3

                                      FORM OF
                       WASTE SYSTEMS INTERNATIONAL, INC.
                 OFFER FOR $77,500,000 PRINCIPAL AMOUNT OF THE
                         11 1/2% SENIOR NOTES DUE 2006
                                IN EXCHANGE FOR
                     11 1/2% SERIES B SENIOR NOTES DUE 2006

To: Brokers, Dealers, Commercial Banks,

    Trust Companies and Other Nominees

    Waste Systems International, Inc. (the "Company"), upon and subject to the
terms and conditions set forth in the Prospectus, dated [            ], 1999
(the "Prospectus"), and the enclosed Letter of Transmittal (the "Letter of
Transmittal"), is offering to exchange (the "Exchange Offer") $77,500,000
principal amount of its 11 1/2% Series B Senior Notes Due 2006 (the "New Senior
Notes") for its outstanding 11 1/2% Senior Notes Due 2006 (the "Old Senior
Notes"). The Exchange Offer is being made in order to satisfy certain
obligations of the Company contained in the Note Registration Rights Agreement
dated as of March 2, 1999, among the Company and the other signatories thereto.

    We are requesting that you contact your clients for whom you hold Old Senior
Notes regarding the Exchange Offer. For your information and for forwarding to
your clients for whom you hold Old Senior Notes registered in your name or in
the name of your nominee, or who hold Old Senior Notes registered in their own
names, we are enclosing the following documents:

    1.  Prospectus dated [            ], 1999;

    2.  The Letter of Transmittal for your use and for the information of your
       clients;

    3.  A Notice of Guaranteed Delivery to be used to accept the Exchange Offer
       if certificates for Old Senior Notes are not immediately available or
       time will not permit all required documents to reach the Exchange Agent
       prior to the Expiration Date (as defined in below) or if the procedure
       for book-entry transfer cannot be completed on a timely basis;

    4.  A form of letter which may be sent to your clients for whose account you
       hold Old Senior Notes registered in your name or the name of your
       nominee, with space provided for obtaining such clients' instructions
       with regard to the Exchange Offer;

    5.  Guidelines for Certification of Taxpayer Identification Number on
       substitute Form W-9; and

    6.  Return envelopes addressed to IBJ Whitehall Bank & Trust Company, the
       Exchange Agent for the Old Senior Notes.

    YOUR PROMPT ACTION IS REQUESTED. THE EXCHANGE OFFER WILL EXPIRE AT 5:00
P.M., EASTERN TIME, ON [            ], 1999, UNLESS EXTENDED BY THE COMPANY (THE
"EXPIRATION DATE"). THE OLD SENIOR NOTES TENDERED PURSUANT TO THE EXCHANGE OFFER
MAY BE WITHDRAWN AT ANY TIME BEFORE THE EXCHANGE AGENT MAILS THE NEW SENIOR
NOTES DUE PURSUANT TO THE TENDER. SEE THE PROSPECTUS UNDER "THE EXCHANGE
OFFER--WITHDRAWAL OF TENDERS."

    To participate in the Exchange Offer, a duly executed and properly completed
Letter of Transmittal (or facsimile thereof), with any required signature
guarantees and any other required documents, should be sent to the Exchange
Agent and certificates representing the Old Senior Notes should be delivered to
the Exchange Agent, all in accordance with the instructions set forth in the
Letter of Transmittal and the Prospectus.

    If holders of Old Senior Notes wish to tender, but it is impracticable for
them to forward their certificates for Old Senior Notes prior to the expiration
of the Exchange Offer or to comply with the book-entry transfer procedures on a
timely basis, a tender may be effected by following the guaranteed delivery
procedures described in the Prospectus under "The Exchange Offer--Procedures for
Tendering."

    The Company will, upon request, reimburse brokers, dealers, commercial banks
and trust companies for reasonable and necessary costs and expenses incurred by
them in forwarding the Prospectus and the related documents to the beneficial
owners of Old Senior Notes held by them as nominee or in a fiduciary capacity.
The Company will pay or cause to be paid all stock transfer taxes applicable to
the exchange of Old Senior Notes pursuant to the Exchange Offer, except as set
forth in Instruction 5 of the Letter of Transmittal.

    Any inquiries you may have with respect to the Exchange Offer, or requests
for additional copies of the enclosed materials, should be directed to IBJ
Whitehall Bank & Trust Company, the Exchange Agent, at its address and telephone
number set forth on the front of the Letter of Transmittal.

                                          Very truly yours,
                                          Robert Rivkin
                                          Executive Vice President,
                                          Chief Financial Officer, Secretary,
                                          Treasurer and Director

    NOTHING HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL CONSTITUTE YOU OR ANY
PERSON AS AN AGENT OF THE COMPANY OR THE EXCHANGE AGENT, OR AUTHORIZE YOU OR ANY
OTHER PERSON TO USE ANY DOCUMENT OR MAKE ANY STATEMENTS ON BEHALF OF EITHER OF
THEM WITH RESPECT TO THE EXCHANGE OFFER, EXCEPT FOR STATEMENTS EXPRESSLY MADE IN
THE PROSPECTUS OR THE LETTER OF TRANSMITTAL.

Enclosures

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