**UNITED
      STATES**


**SECURITIES
      AND EXCHANGE COMMISSION**


**Washington,
      D.C. 20549**







**FORM
      10-K/A**


**AMENDMENT
      NO. 2**




**ý**  **ANNUAL
      REPORT PURSUANT TO SECTION 13 OR 15(d)**


**OF
      THE SECURITIES EXCHANGE ACT OF 1934**





**For
      the fiscal year ended October 31, 2005**


**Commission
      File Number 0-26670**





**NORTH
      AMERICAN SCIENTIFIC, INC.**


(Exact
      name of registrant as specified in its charter)





**Delaware**
            **51-0366422**(State
                or other jurisdiction of
                incorporation)
            (I.R.S.
                Employer Identification
                No.)





**20200
      Sunburst Street, Chatsworth, California 91311**


(Address
      of principal executive offices) (Zip Code)




**(818)
      734-8600**


(Registrant’s
      telephone number, including area code)




Securities
      registered pursuant to Section 12(b) of the Act: **None**


Securities
      registered pursuant to Section 12(g) of the Act:


**Common
      Stock, par value $0.01 per share**


(Title
      of
      class)









Indicate
      by check mark if the registrant is a well-known seasoned issuer, as defined
      in
      Rule 405 of the Securities Act. o Yes  ý No




Indicate
      by check mark if the registrant is not required to file reports pursuant to
      Section 13 or Section 15(d) of the Act. o Yes  ý No




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. ý Yes o 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 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. ý




Indicate
      by check mark whether the registrant is a large accelerated filer, an
      accelerated filer, or a non-accelerated filer. See definition of “accelerated
      filer” and “large accelerated filer” in Rule 12b-2 of the Securities Exchange
      Act of 1934.࿠




o Large
      Accelerated Filer  ý Accelerated Filer  o Non-Accelerated Filer




Indicate
      by check mark whether registrant is a shell company (as defined in Rule 12b-2
      of
      the Act). o Yes  ý No




The
      aggregate market value of voting stock held by non-affiliates of the Registrant
      was approximately $35.7 million (based upon the price at which the common stock
      was last sold, as of the last business day of the Registrant's most recently
      completed second fiscal quarter).




As
      of
      February 17, 2006, approximately 16,988,869 shares of the Registrant's Common
      Stock, $.01 par value per share, were outstanding.









**EXPLANATORY
      NOTE**




North
      American Scientific, Inc. (the “Company”) is filing this Amendment No. 2 on Form
      10-K/A to amend its Annual Report on Form 10-K for the fiscal year ended October
      31, 2005, as originally filed with the Securities and Exchange Commission (the
      “Commission”) on January 18, 2006 (the “Original Form 10-K”) and subsequently
      amended by Amendment No. 1 on Form 10-K/A as filed with the Commission on
      February 28, 2006, for the sole purpose of correcting the inadvertent omission
      of certain references to internal control over financial reporting that
      were required to be provided in the Section 302 Certifications of our
      principal executive officer and our principal financial officer as filed in
      the
      Company’s Original Form 10-K. The required references to internal control over
      financial reporting have been included in paragraph 3 and paragraph 3(b) in
      the
      Section 302 Certifications filed with this Amendment No. 2. There are no changes
      to the Company’s financial statements as originally filed. There are also no
      changes to the disclosures in the Original Form 10-K or Amendment No. 1. This
      Amendment No. 2 continues to speak as of the date of the Original Form 10-K,
      and
      the Company has not updated the disclosure contained herein to reflect any
      events that occurred at a later date.




**PART
      IV**




**Item
      15. Exhibits and Financial Statement Schedules.**




**Exhibit
      No.**   **Description**




31.1   Certification
      of Chief Executive Officer pursuant to Section 302 of the  Sarbanes-Oxley
      Act.




31.2  Certification
      of Chief Financial Officer pursuant to Section 302 of the Sarbanes-Oxley Act.











**SIGNATURES**







Pursuant
      to the requirements of Section 13 or 15(d) of the Securities Exchange Act of
      1934, the Registrant has duly caused this Amendment No. 2 to Form 10-K to be
      signed on its behalf by the undersigned thereunto duly authorized.





**NORTH
                AMERICAN SCIENTIFIC, INC.**Date: June
              2,
              2006
            By:
            /s/ L.
              Michael CutrerName:L.
              Michael CutrerTitle:   President and Chief Executive
              Officer