MIRAVANT MEDICAL TECHNOLOGIES
EXHIBIT 10.4 - SIDE LETTER AGREEMENT
<DOCUMENT>
<TYPE>EX-10
<SEQUENCE>3
<FILENAME>sideletter.txt
<DESCRIPTION>EXHIBIT 10.4 - SIDE LETTER AGREEMENT
<TEXT>
Exhibit 10.4

                              SIDE LETTER AGREEMENT


                                 August 28, 2003



TO: The Investors Listed on Schedule 1 and Schedule 2 Attached Hereto

Re:  Certain   Agreements  With  Respect  To  Investment  in  Miravant   Medical
Technologies

     This Side Letter Agreement is executed in connection with: (i) that certain
Convertible  Debt and Warrant  Purchase  Agreement  dated December 19, 2002 (the
"Original  Purchase  Agreement") by and among Miravant Medical  Technologies,  a
Delaware  corporation  (the  "Company"),  and the investors listed on Schedule 1
attached  hereto,  as  successors  to Princess  Finance  Limited,  a BVI company
("Princess"  and,  together  with such  investors  listed on Schedule 1 attached
hereto, the "Original  Investors");  and (ii) that certain Unsecured Convertible
Debenture  and  Warrant  Purchase  Agreement  of even  date  herewith  (the "New
Purchase  Agreement") by and among the Company, the investors listed on Schedule
2  attached  hereto  (the  "New  Princess  Investors")  and  certain  additional
investors (collectively, the "New Investors").

     The  Original  Investors  are the  holders  of the  convertible  notes (the
"Notes") and warrants (the "Note  Warrants")  issued by the Company  pursuant to
the Original Purchase  Agreement.  The Company is entering into the New Purchase
Agreement for the sale and issuance of convertible debentures (the "Debentures")
and warrants (the "Debenture  Warrants") to the New Investors (including the New
Princess Investors).  In connection with and as a condition to closing under the
New Purchase  Agreement,  the Original Investors and the Company are required to
enter  into a  certain  Subordination  Agreement  with the New  Investors,  such
agreement to be in  substantially  the form as attached hereto as Exhibit A (the
"Subordination Agreement").

     As an inducement to the Original  Investors entering into the Subordination
Agreement  with the New Investors,  and as a further  condition to closing under
the New Purchase  Agreement,  and for other good and valuable  consideration the
receipt  and  sufficiency  of which is hereby  acknowledged,  the  Company,  the
Original  Investors  and the New  Princess  Investors,  intending  to be legally
bound, hereby agree as follows:

     1. Upon issuance of the Debentures and Debenture  Warrants  pursuant to the
terms of the New Purchase Agreement,  the Company shall issue to (i) Princess an
additional warrant,  in the same form as the Note Warrants,  to purchase 787,500
shares of the  Company's  Common Stock at an Exercise  Price of $1.00 per share,
and (ii) Saules Holdings,  Limited (which, for all purposes hereunder,  shall be
deemed to be an "Original  Investor") an additional warrant, in the same form as
the Note Warrants,  to purchase  787,500 shares of the Company's Common Stock at
an Exercise Price of $1.00 per share (collectively, the "Adjustment Warrants").

     2. Upon issuance of the Debentures and Debenture  Warrants  pursuant to the
terms of the New  Purchase  Agreement,  pursuant to Section 4.4 of the  Original
Purchase  Agreement,  the  Exercise  Price  of  each  Note  Warrant  issued  and
outstanding as of the date hereof (excluding the Loan Origination Warrant) shall
be adjusted to equal $1.00 per share.

     3. Upon issuance of the Debentures and Debenture  Warrants  pursuant to the
terms of the New  Purchase  Agreement,  pursuant to Section 4.4 of the  Original
Purchase Agreement,  the Conversion Price of each Note issued and outstanding as
of the date hereof  (excluding  the Notes  issued in  December  2002 and January
2003) shall be adjusted to equal $1.00 per share.

     4. In order to document additional "Purchasers" under the Original Purchase
Agreement  and previous  transfers of Notes and Note  Warrants by Princess,  the
following  entities are each made party to the Original Purchase  Agreement as a
"Purchaser"  and each agrees to be bound by the Original  Purchase  Agreement as
such:

                  (i)      GORUMNA, LTD.;
                  (ii)     PLEYEL HOLDINGS, LIMITED;
                  (iii)    BIG CAT CAPITAL, LIMITED;
                  (iv)     ACACIAS FINANCIAL, LIMITED;
                  (v)      ALERT INVESTMENTS, LIMITED;
                  (vi)     CAMELFORD HOLDINGS, LIMITED;
                  (vii)    DANUBE FINANCIAL, LIMITED;
                  (viii)   DELICE FINANCIAL, LIMITED;
                  (ix)     IRIS FINANCIAL, LIMITED;
                  (x)      PEARL WAVES, INC;
                  (xi)     Tioman Finance Limited;
                  (xii)    Morebath Holdings Limited;
                  (xiii)   Kinaro Investments S.A.; and
                  (xiv)    SAULES Holdings, Limited.

     5. Each  Original  Investor and New Princess  Investor  acknowledges  that,
pursuant to Section 4.19 of the New Purchase Agreement,  the Company is required
to solicit the vote of the  stockholders for the approval of an amendment to the
Company's  Certificate of  Incorporation  (the "Charter  Amendment") that would,
among other things,  increase the number of  authorized  shares of the Company's
Common Stock to 65,000,000  shares (the "Stockholder  Approval").  Each Original
Investor agrees that, unless and until such time as the Company has obtained the
Stockholder  Approval and the Charter Amendment has been filed with the State of
Delaware and become effective,  such Original Investor shall not (a) convert any
Notes  currently  held or hereafter  acquired by such  Original  Investor to the
extent that the shares of Common Stock  issuable  upon  conversion of such Notes
are not as of the date hereof registered for resale on an effective registration
statement  filed under the Securities  Act of 1933, as amended (the  "Securities
Act"); or (b) exercise any Note Warrants currently held or hereafter acquired by
such Original  Investor  (including the Adjustment  Warrants) to the extent that
the shares of Common Stock  issuable upon exercise of such Note Warrants are not
as of the  date  hereof  registered  for  resale  on an  effective  registration
statement filed under the Securities Act. Each Original Investor  represents and
warrants  that the number of Notes and Note  Warrants  subject to the  foregoing
restriction  on  conversion  and exercise  (described  in terms of the number of
shares of Common Stock  issuable upon  exercise or conversion  thereof) that are
held by such Original Investor are accurately set forth on Schedule 1 hereto. In
furtherance  of the foregoing  restriction on conversion and exercise of certain
Notes and Note Warrants held or acquired by the Original Investors, the Original
Investors  further  agree  that,  unless and until such time as the  Company has
obtained the Stockholder  Approval and the Charter Amendment has been filed with
the State of Delaware and become effective:

     (i)   compliance   by  the  Company  with  the   covenants   regarding  the
authorization  and  reservation  of  shares of Common  Stock for  issuance  upon
conversion or exercise of such Notes and Note Warrants,  as set forth in Section
4(c) of the  Notes and  Sections  5(b) and (d) of the Note  Warrants,  is hereby
irrevocably waived;

     (ii) any default  provisions  in the Notes or Note  Warrants  relating to a
failure by the  Company to honor a  conversion  or  exercise  thereof are hereby
irrevocably waived; and

     (iii)  notwithstanding  the provisions of Sections  2(a),  2(c) and 3(b) of
that certain  Registration Rights Agreement dated as of December 19, 2002 by and
among the Company and the Original Investors (the "Original  Registration Rights
Agreement"),  the Company  shall not be  required to register  the resale of the
Registrable  Securities  (as such term is defined in the  Original  Registration
Rights Agreement)  issuable upon conversion or exercise of or otherwise pursuant
to the Notes and Note Warrants held by the Original Investors that are not as of
the date hereof already registered for resale.

     6. Each New Princess  Investor  agrees that,  unless and until such time as
the Company has obtained the Stockholder  Approval and the Charter Amendment has
been filed with the State of Delaware  and become  effective,  such New Princess
Investor  shall not (a)  convert  any  Debentures  currently  held or  hereafter
acquired by such New Princess  Investor;  or (b) exercise any Debenture Warrants
currently  held  or  hereafter  acquired  by  such  New  Princess  Investor.  In
furtherance  of the  foregoing  restriction  on  conversion  and exercise of the
Debentures  and  Debenture  Warrants  held  or  acquired  by  the  New  Princess
Investors,  the New Princess Investors further agree that, unless and until such
time as the  Company  has  obtained  the  Stockholder  Approval  and the Charter
Amendment has been filed with the State of Delaware and become effective:

     (i)   compliance   by  the  Company  with  the   covenants   regarding  the
authorization  and  reservation  of  shares of Common  Stock for  issuance  upon
conversion or exercise of their Debentures and Debenture Warrants,  as set forth
in Section 4.5 of the New Purchase Agreement, Section 4(d) of the Debentures and
Section 5(b) of the Debenture Warrants, is hereby irrevocably waived;

     (ii) compliance by the Company with the covenants  regarding the listing of
the  shares of Common  Stock  issuable  upon  conversion  or  exercise  of their
Debentures  and  Debenture  Warrants,  as set forth in  Section  4.11 of the New
Purchase  Agreement  and  Section  5(c) of the  Debenture  Warrants,  is  hereby
irrevocably waived;

     (iii) any default  provisions in the Debentures and the Debenture  Warrants
relating to a failure by the Company to honor a conversion  or exercise  thereof
are hereby irrevocably waived;

     (iv) notwithstanding the provisions of Sections 2(a), 2(c) and 3(c) of that
certain  Registration  Rights  Agreement of even date  herewith by and among the
Company and the New Investors (the "New  Registration  Rights  Agreement"),  the
Company  shall  not be  required  to  register  the  resale  of the  Registrable
Securities (as such term is defined in the New  Registration  Rights  Agreement)
issuable upon conversion or exercise of or otherwise  pursuant to the Debentures
and Debenture Warrants held by the New Princess Investors;

     (v)  the  penalty   provisions  set  forth  in  Section  2(b)  of  the  New
Registration  Rights  Agreement are  irrevocably  waived as to such  Registrable
Securities  until such time as the Company  becomes  obligated  to register  the
resale  of such  Registrable  Securities  pursuant  to  Section  3(c) of the New
Registration Rights Agreement; and

     (vi) the 150-day period  referenced in Section 5(h) of the Debentures shall
not be  deemed to  commence,  with  respect  to the  Debentures  held by the New
Princess  Investors only, until the date on which the Company becomes  obligated
to register the resale of the Registrable Securities issuable upon conversion of
such Debentures as provided in clause (iv) above.

     7. The Notes and Note  Warrants  that are  subject to the  restrictions  on
conversion  and exercise set forth in Paragraph 5 above and the  Debentures  and
Debenture  Warrants  that are  subject to the  restrictions  on  conversion  and
exercise set forth in Paragraph 6 above are referred to herein  collectively  as
the  "Restricted  Securities."  With respect to all  Restricted  Securities,  in
furtherance  of the  restrictions  on  conversion  and  exercise  set  forth  in
Paragraphs 5 and 6 above, the Original  Investors and the New Princess Investors
further  agree that,  unless and until such time as the Company has obtained the
Stockholder  Approval and the Charter Amendment has been filed with the State of
Delaware and become effective:

     (i) the Company shall have no obligation to honor, and shall be entitled to
instruct its transfer agent not to honor, any attempts by any Original  Investor
or New Princess Investor to convert or exercise any Restricted Securities;

     (ii) the Company  shall be entitled to place the  following  legend on each
Restricted  Security  (and,  to the extent the Original  Investors  already have
possession of such Restricted  Securities,  the Original  Investors shall return
such  Restricted  Securities  to the Company for the  placement of the following
legend thereon):

                  ADDITIONAL RESTRICTIONS ON THE [CONVERSION/ EXERCISE] AND
                  TRANSFER OF THIS [NOTE/ DEBENTURE/ WARRANT] ARE SET FORTH IN A
                  CERTAIN SIDE LETTER AGREEMENT DATED AS OF AUGUST 28, 2003, AS
                  AMENDED FROM TIME TO TIME, AMONG THE COMPANY AND THE HOLDER
                  HEREOF, A COPY OF WHICH IS ON FILE WITH THE SECRETARY OF THE
                  COMPANY AND MAY BE OBTAINED BY THE HOLDER HEREOF WITHOUT
                  CHARGE.

; and

     (iii) notwithstanding the terms of the Original Purchase Agreement, the New
Purchase Agreement or the Restricted Securities themselves, no Original Investor
or New Princess  Investor may transfer or assign any Restricted  Securities,  or
any of its rights therein,  to any other person or entity unless such transferee
or assignee has agreed in writing to be bound by the restrictions on conversion,
exercise and transfer set forth in this Side Letter Agreement.

     8. Except as otherwise  provided in this Side Letter  Agreement,  the terms
and  conditions  of  each  of the  Original  Purchase  Agreement,  the  Original
Registration  Rights Agreement,  the Notes, the Note Warrants,  the New Purchase
Agreement, the New Registration Rights Agreement, the Debentures,  the Debenture
Warrants and all other agreements  entered into in connection with the foregoing
shall remain in full force and effect.

     9. This  Side  Letter  Agreement  shall be  governed  by and  construed  in
accordance  with the laws of the State of Delaware  applicable to contracts made
and to be performed in the State of Delaware.

     10. This Side Letter Agreement may be executed in two or more counterparts,
including,   without  limitation,  by  facsimile  transmission,   all  of  which
counterparts  shall be  considered  one and the same  agreement and shall become
effective when  counterparts have been signed by each party and delivered to the
other parties hereto.

     11. If any  provision  of this Side  Letter  Agreement  shall be invalid or
unenforceable in any jurisdiction, such invalidity or unenforceability shall not
affect the  validity  or  enforceability  of the  remainder  of this Side Letter
Agreement or the validity or enforceability of this Side Letter Agreement in any
other jurisdiction.

     12. The New Investors (other than the New Princess Investors) are expressly
intended to be third party  beneficiaries  of this Side  Letter  Agreement  with
respect to all obligations and agreements of the Original  Investors and the New
Princess  Investors.  No provision of this Side Letter  Agreement  may be waived
other than by an  instrument  in writing  signed by the party to be charged with
enforcement (including, in the case of the Company, each New Investor other than
the New Princess  Investors),  and no provision of this Agreement may be amended
other than by an  instrument  in writing  signed by the Company,  each  Original
Investor, each New Princess Investor and each New Investor.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]


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     Please  indicate your  acceptance of the terms and  conditions of this Side
Letter Agreement by signing where indicated below.

                                       MIRAVANT MEDICAL TECHNOLOGIES,
                                       a Delaware corporation

                                       By:    /s/Gary S. Kledzik
                                        -------------------------------------
                                        Gary S. Kledzik, Chief Executive Officer


ACKNOWLEDGED AND AGREED:

PRINCESS FINANCE LIMITED
GORUMNA, LTD.
PLEYEL HOLDINGS, LIMITED
BIG CAT CAPITAL, LIMITED
ACACIAS FINANCIAL, LIMITED
ALERT INVESTMENTS, LIMITED
CAMELFORD HOLDINGS, LIMITED
DANUBE FINANCIAL, LIMITED
DELICE FINANCIAL, LIMITED
IRIS FINANCIAL, LIMITED
PEARL WAVES, INC
Tioman Finance Limited
Morebath Holdings Limited
Kinaro Investments S.A.
SAULES INVESTMENTS S.A.
BOMOSEEN INVETMENTS, LD
DANDELION INTERNATIONAL, LTD.
SILVER CREEK INVESTMENTS, LTD.


By:         /s/ Robert T. Tucker
   -------------------------------------------------------
     Robert T. Tucker, Attorney-in-Fact for all of the above


<PAGE>


                                                    Schedule 1

                                                Original Investors

--------------------------------- - --------------- -- ------------------ -----
                                    Note Shares        Warrant Shares
                                    Subject to         Subject to Side
                                    Side Letter        Letter

--------------------------------- - --------------- -- ------------------ -----
Gorumna, Ltd.                        72,913            ---
--------------------------------- - --------------- -- ------------------ -----
Pleyel Holdings, Limited             72,913            ---
--------------------------------- - --------------- -- ------------------ -----
Big Cat Capital, Limited             72,913            ---
--------------------------------- - --------------- -- ------------------ -----
Alert Investments, Limited           72,913            ---
--------------------------------- - --------------- -- ------------------ -----
Camelford Holdings, Limited          72,913            ---
--------------------------------- - --------------- -- ------------------ -----
Acacias Financial Limited            72,913            ---
--------------------------------- - --------------- -- ------------------ -----
Pearl Waves, Inc.                    72,913            ---
--------------------------------- - --------------- -- ------------------ -----
Danube Financial, Limited            72,913            ---
--------------------------------- - --------------- -- ------------------ -----
Delice Financial, Limited            72,913            ---
--------------------------------- - --------------- -- ------------------ -----
Iris Financial, Limited              72,913            ---
--------------------------------- - --------------- -- ------------------ -----
Tioman Finance Limited              277,736            25,000
--------------------------------- - --------------- -- ------------------ -----
Morebath Holdings Limited           277,737            25,000
--------------------------------- - --------------- -- ------------------ -----
Kinaro Investments S.A              277,735            25,000
--------------------------------- - --------------- -- ------------------ -----
Saules Holding, Limited             ---                787,500
--------------------------------- - --------------- -- ------------------ -----
Princess Finance, Limited           ---                787,500
--------------------------------- - --------------- -- ------------------ -----
         Totals:                    1,562,338          1,650,000
--------------------------------- - --------------- -- ------------------ -----




<PAGE>


                                                    Schedule 2

                                              New Princess Investors

Bomoseen Investments, Ltd.
Dandelion International, Ltd.
Silver Creek Investments, Ltd.

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