Exhibit 99.1

                             GRUSHKO & MITTMAN, P.C.
                                Attorneys at Law
                          551 FIFTH AVENUE, SUITE 1601
                            NEW YORK, NEW YORK 10176
                           (212) 697-9500 (Telephone)
                           (212) 697-3575 (Telecopier)
                           COUNSLERS@AOL.COM (e-mail)

                                  May 27, 2003

Via Telecopier (973) 427-5455
And First Class Mail

Tech Laboratories, Inc.
955 Belmont Avenue
North Haledon, New Jersey 07508

Attn:  Bernard M. Ciongoli

                                    Re:     Tech Laboratories, Inc.
                                            Notice of Non-Payment and Default

Dear Mr. Ciongoli:

     We  represent  Celeste  Trust Reg.  and  Esquire  Trade & Finance,  Inc. in
connection  with  Convertible  Notes issued by Tech  Laboratories,  Inc.  ("Tech
Labs") on October 13, 2000.

     Pursuant to the terms of the  Amendment to the  Redemption  and  Conversion
Agreement  entered  into among Tech Labs and the Note Holders on April 19, 2002,
failure by Tech Labs to make  scheduled  payments will void the  Redemption  and
Conversion  Agreement  and all rights and  obligations  will be  governed by the
terms of the original Subscription  Agreement and Notes. Tech Labs has failed to
make the  scheduled  payments.  The  maturity  date of the Notes was October 13,
2002.  The  Company  is now in  default  under  the  terms  of the  Subscription
Agreement and Notes.  Presently,  principal  outstanding  on the Notes issued to
each of Celeste Trust Reg. and Esquire Trade & Finance, Inc. is $380,000.

     Following the occurrence of an event of default,  all sums of principal and
interest then remaining unpaid and all other amounts payable under the Notes are
due and payable immediately.  Pursuant to the Subscription Agreement, liquidated
damages in the amount of 2% per month for the first  thirty days and  thereafter
3% per thirty days begin to accrue.  As of May 31,




Mittman to Tech Labs
Page -2-
May 27, 2003

2003,  liquidated  damages  in the  amount of  $129,700  will be due and  owing,
together  with  interest of $32,499 for each of Celeste  Trust Reg.  and Esquire
Trade & Finance, Inc.

     Demand is hereby made for the payment on or before June 7, 2003 of $542,199
for each of Celeste  Trust Reg. and Esquire  Trade & Finance,  Inc. In the event
full payment is not received,  legal action will be commenced.  This action will
most likely  include the filing of an  involuntary  petition in bankruptcy and a
request for the appointment of a receiver.

     Kindly advise your auditors of these  outstanding  liabilities so that they
may be properly  reflected on Tech Lab's financial  statements and reports filed
with the Securities and Exchange Commission.


                                                   Very truly yours,

                                                   GRUSHKO & MITTMAN, P.C.


                                                   /s/ Barbara R. Mittman
                                                   ------------------------
                                                   Barbara R. Mittman

BRM:al

cc:      Celeste Trust Reg.
         Esquire Trade & Finance, Inc.
         Walter Stursberg, Esq.