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                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                  FORM 10-K/A-1

(Mark One)
[X]  ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE
     ACT OF 1934 [NO FEE REQUIRED]

                  FOR THE FISCAL YEAR ENDED: DECEMBER 31, 2003
                                       OR

[ ]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
     EXCHANGE ACT OF 1934 [NO FEE REQUIRED]

           For the transition period from ________________ to __________________

                           COMMISSION FILE NO. 0-27432

                         CLEAN DIESEL TECHNOLOGIES, INC.
                         -------------------------------
             (Exact name of registrant as specified in its charter)


     Delaware                                                   06-1393453
-------------------------------                           ----------------------
(State or other jurisdiction of                              (I.R.S. Employer
incorporation of organization)                            Identification Number)

                         SUITE 702, 300 ATLANTIC STREET
                               STAMFORD, CT 06901
                                 (203) 327-7050
          -------------------------------------------------------------
          (Address and telephone number of principal executive offices)

        SECURITIES REGISTERED PURSUANT TO SECTION 12(b) OF THE ACT: NONE

           SECURITIES REGISTERED PURSUANT TO SECTION 12(g) OF THE ACT:

                     COMMON STOCK $0.05 PAR VALUE PER SHARE
                     --------------------------------------
                                (Title of Class)

Indicate  by  check  mark  whether  the  registrant:  (1)  has filed all reports
required  to  be  filed by Section 13 or 15(d) of the Securities Exchange Act of
1934  during  the  preceding  12  months  (or  for  such shorter period that the
registrant  was required to file such reports), and (2) has been subject to such
filing  requirements  for  the  past  90  days.

                               Yes  X     No
                                   ---       ---

Indicate  by  check mark if disclosure of delinquent filers pursuant to Item 405
of  Regulation  S-K  is  not contained herein, and will not be contained, to the
best  of  the  registrant's  knowledge,  in  definitive  proxy  or  information
statements  incorporated  by  reference  in  Part  III  of this Form 10-K or any
amendment  to  this  Form  10-K.     X
                                    ---

Indicate  by  check  mark  whether  the  registrant  is an accelerated filer (as
defined  in  Rule  12b-2  of  the  Act).

                               Yes        No  X
                                   ---       ---

Aggregate  market  value  of  the  voting  stock  held  by non-affiliates of the
registrant  based  on  the  average  bid  and  asked prices as of June 30, 2003:
$2.65   and  as  of  March  19,  2004:  $3.02

Indicate  number  of  shares  outstanding  of  each of the registered classes of
Common Stock at March 25, 2004: 15,679,337 shares Common Stock, $0.05 par value.
Certain  portions  of the Proxy Statement for the annual meeting of stockholders
to  be  held  in  2003  are  incorporated by reference into parts II, III and IV
hereof.
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                                EXPLANATORY NOTE

     This  is  an amendment of the Clean Diesel Technologies, Inc. Annual Report
to  the Commission on Form 10-K for the period ended December 31, 2003 which was
previously  filed on March 24, 2004 (the "10-K").  The purpose of this amendment
is to note that the legend "Draft Subject to Revision" was inadvertently left on
the  Auditors  Report  in  Item  8 of the electronic transmission of the 10-K as
filed.  Such  legend  was, however, not in fact a part of the Auditors Report as
signed.  The  10-K  is  otherwise  complete  and  correct  as  submitted.


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                                   SIGNATURES

     Pursuant  to  the  requirements  of  Section  13 or 15(d) of the Securities
Exchange  Act  of  1934,  Clean  Diesel  Technologies, Inc. has duly caused this
amendment  to  the  report  on  Form  10-K  to  be  signed  on its behalf by the
undersigned,  thereunto  duly  authorized.

                                  CLEAN DIESEL TECHNOLOGIES, INC.


   March 29, 2004                 By:  /s/  Jeremy D. Peter-Hoblyn
-------------------                  ------------------------------------
     Date                                   Jeremy D. Peter-Hoblyn
                                            Chief Executive Officer and Director


     Pursuant  to  the  requirements of the Securities Exchange Act of 1934, the
following  persons  on  behalf  of  Clean  Diesel  Technologies, Inc. and in the
capacities  and  on  the  date  indicated  have  duly  signed this report below.


     /s/ Jeremy D. Peter-Hoblyn  Chief Executive Officer and Director
     --------------------------  (principal executive officer)
       Jeremy D. Peter-Hoblyn


     /s/ David W. Whitwell       Chief Financial Officer, Vice President, and
     --------------------------  Treasurer
        David W. Whitwell        (principal financial and accounting officer)


     /s/ John A. de Havilland    Director
     --------------------------
       John A. de Havilland


     /s/ Derek R. Gray           Director, Non-Executive Chairman of the Board
     --------------------------  of Directors
            Derek R. Gray


     /s/ Charles W. Grinnell     Director, Vice President, and Corporate
     --------------------------  Secretary
         Charles W. Grinnell


     /s/ James M. Valentine     Director and President
     ----------------------
       James M. Valentine




     Dated: March 29, 2004


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