UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                                    FORM 8-K

                                 CURRENT REPORT

                       Pursuant to Section 13 or 15(d) of
                       the Securities Exchange Act of 1934

       Date of Report (Date of earliest event reported): December 30, 2005

                           DUSA PHARMACEUTICALS, INC.
             (Exact name of registrant as specified in its charter)

            NEW JERSEY              0-19777             22-3103129
         (State or other       (Commission File        (IRS Employer
         jurisdiction of            Number)           Identification
          incorporation)                                  Number)

                                 25 UPTON DRIVE
                         WILMINGTON, MASSACHUSETTS 01887
          (Address of principal executive offices, including ZIP code)

                                 (978) 657-7500
              (Registrant's telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2. below):

[ ]   Written communications pursuant to Rule 425 under the Securities Act (17
      CFR 230.425)

[ ]   Soliciting material pursuant to Rule 14a-12 under the Securities Act (17
      CFR 240.14a-12)

[ ]   Pre-commencement communications pursuant to Rule 14d-2(b) under the
      Exchange Act (17 CFR 240.14d-2(b))

[ ]   Pre-commencement communications pursuant to Rule 13e-4(c) under the
      Exchange Act (17 CFR 240.13e-4(c))

ITEM 1.01 - ENTRY INTO A MATERIAL DEFINITIVE AGREEMENT.

DUSA Pharmaceuticals, Inc. ("DUSA") issued a press release on January 3, 2006,
attached to and made a part of this report as Exhibit 99, announcing that it had
signed a definitive Merger Agreement ("Merger Agreement") to acquire all of the
common stock of Sirius Laboratories, Inc. ("Sirius") of Vernon Hills, Illinois
in exchange for cash and common stock of DUSA worth up to $30,000,000. The
parties intend that the transaction be structured as a tax-free reorganization
pursuant to Section 368(a) of the Internal Revenue Code of 1986, as amended.
Sirius is a privately held dermatology specialty pharmaceuticals company
founded in 2000 with a primary focus on the treatment of acne vulgaris and acne
rosacea. The Merger Agreement was signed by DUSA, Sirius and certain
shareholders of Sirius on December 30, 2005.             

Of the $30,000,000, $8,000,000 less certain expenses will be paid in cash upon
closing, $17,000,000 will be paid in shares of DUSA's common stock also on
closing, $3,000,000 of which will be subject to escrow, and up to $5,000,000 in
cash or common stock may be paid based on a combination of new product
approvals or launches and the achievement of certain pre-determined total
cumulative sales milestones for Sirius products. The number of shares of DUSA
common stock is based on DUSA's average closing price during the twenty (20)
trading days preceding the public announcement of the Merger Agreement or the
last twenty (20) trading days in the month in which the trigger of a milestone
occurs, if applicable. The parties intend that the DUSA shares will be issued
as a private placement pursuant to Regulation D. Closing of the transaction is
expected in the first quarter of 2006.                          

Further, the Merger Agreement provides for certain conditions precedent to
closing, including, but not limited to, (i) the approval of the transaction and
the terms and conditions of the Merger Agreement by the Sirius shareholders,
(ii) the receipt by DUSA of audited financial statements of Sirius for the
fiscal years ended 2003, 2004 and 2005, and (iii) the determination by DUSA that
the third party manufacturing and distribution facilities used by Sirius to
manufacture or distribute its products, as the case may be, are in material
compliance with all applicable legal requirements and that the third party
manufacturing facilities have the reasonable capability of continuing to
manufacture Sirius' products in compliance with cGMP. In addition, the Merger
Agreement provides DUSA, Sirius and certain Sirius shareholders with the right
to terminate the Merger Agreement under certain circumstances. The parties have
also made customary representations, warranties and covenants in the Merger
Agreement.

The securities to be issued by DUSA in the transaction have not been registered
under the Securities Act of 1933, as amended, and may not be offered or sold in
the United States absent registration or an applicable exemption from
registration. While certain of the DUSA shares will be subject to lock-up
provisions for a period of time, DUSA has agreed to file a registration
statement on Form S-3 with the Securities and Exchange Commission following the
closing for purposes of registering the resale of the common stock issued in the
transaction.

This report shall not constitute an offer to sell or the solicitation of an
offer to sell or the offer to buy or the solicitation of an offer to buy any
securities, nor shall there be any sale of securities in any jurisdiction in
which such offer, solicitation or sale would be unlawful prior to registration
or qualification under the securities laws of any such jurisdiction or in which
there is no applicable exemption from such registration or qualification
requirements. No offering of securities shall

be made except by means of a prospectus meeting the requirements of Section 10
of the Securities Act of 1933, as amended, or an applicable exemption therefrom.

Except for historical information, this report, including the attached exhibit,
contains certain forward-looking statements that involve known and unknown risk
and uncertainties, which may cause actual results to differ materially from any
future results, performance or achievements expressed or implied by the
statements made. These forward-looking statements relate to the closing of the
transaction, beliefs regarding synergies between the companies, expectations for
product offerings and pipeline opportunities, the payment of the consideration,
the intention to lock-up certain shares, the expansion of DUSA's dermatology
focus, and expectations for a stronger entity. Furthermore, the factors that may
cause differing results include the uncertainties of completing the transaction,
the marketplace acceptance of the products, product development risks, reliance
on third party manufacturers, other risks identified in DUSA's SEC filings from
time to time.

ITEM 9.01 - FINANCIAL STATEMENT AND EXHIBITS.



Item No.    Description
--------    -----------
         
99          Press Release, dated January 3, 2006


                                   SIGNATURES

      Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.


                                          DUSA PHARMACEUTICALS, INC.



Dated: January 4, 2006                    By: /s/ D. Geoffrey Shulman
                                              ----------------------------------
                                              D. Geoffrey Shulman, MD, FRCPC
                                              Chairman of the Board and Chief
                                              Executive Officer

                                  EXHIBIT INDEX



Item No.    Description
--------    -----------
         
99          Press Release, dated January 3, 2006