content: Page 1 of 6 pages
  
                                    UNITED STATES
                         SECURITIES AND EXCHANGE COMMISSION
                               Washington, D.C. 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): May 18, 1998
  
  
  
                             MOLECULAR BIOSYSTEMS, INC.
               (Exact name of registrant as specified in its charter)
  
  
  
                            Delaware 1-10546 36-30878632
                (State or other juris- (Commission file (IRS employer
              diction of incorporation) number) identification number)
  
  
  
                10070 Barnes Canyon Road, San Diego, California 92121
                      (Address of principal executive offices)
  
  
  
         Registrant's telephone number, including area code: (619) 812-7001
  
  
  
  
  
  
  
  
  <PAGE>
  
  
  Item 5.  Other Events.
  
           Final European Approval of OPTISONtm
  
           On May 18, 1998,  OPTISON,  the  Company's  second-generation  contrast
  agent for cardiac ultrasound imaging,  received final marketing authorization by
  the European Agency for the Evaluation of Medicinal Products for use in patients
  with suspected or known cardiovascular  disease. The authorization covers all 15
  member states of the European Union.
  
           A copy of the  press  release  that the  Company  jointly  issued  with
  Mallinckrodt, Inc., on May 19, 1998, is attached to this Report as Exhibit 10.1.
  Mallinckrodt, Inc., is the Company's marketing partner for OPTISON in the United
  States and most other regions of the world.
  
  
  
  
  
  <PAGE>
  
  
                                    Signature
             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.
  
             Date:   May 22, 1998.
  
  
             Molecular Biosystems, Inc.
  
  
  
             By       /s/ Gerard A. Wills
                      Gerard A. Wills
                      Vice President, Finance
                        and Chief Financial Officer
  
  
  
  
  <PAGE>
  
  
                                   Exhibit Index
                                                                Sequentially
       Exhibit         Description                              Numbered Page
  
       10.1            Press release (May 19, 1998)                  5
metadata_documents: [{"type": "8-K", "sequence": "1", "description": "8-K", "secsgml_size_bytes": 2481}]
metadata_filer: {"company-data": {"conformed-name": "MOLECULAR BIOSYSTEMS INC", "cik": "0000719598", "assigned-sic": "2835", "irs-number": "363078632", "state-of-incorporation": "DE", "fiscal-year-end": "0331"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "001-10546", "film-number": "98630048"}, "business-address": {"street1": "10070 BARNES CANYON RD", "city": "SAN DIEGO", "state": "CA", "zip": "92121-2789", "phone": "6198242200"}, "mail-address": {"street1": "10070 BARNES CANYON ROAD", "city": "SAN DIEGO", "state": "CA", "zip": "92121"}}
text: Page 1 of 6 pages
  
                                    UNITED STATES
                         SECURITIES AND EXCHANGE COMMISSION
                               Washington, D.C. 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): May 18, 1998
  
                             MOLECULAR BIOSYSTEMS, INC.
               (Exact name of registrant as specified in its charter)
  
                            Delaware 1-10546 36-30878632
                (State or other juris- (Commission file (IRS employer
              diction of incorporation) number) identification number)
  
                10070 Barnes Canyon Road, San Diego, California 92121
                      (Address of principal executive offices)
  
         Registrant's telephone number, including area code: (619) 812-7001
  Item 5.  Other Events.
  
           Final European Approval of OPTISONtm
  
           On May 18, 1998,  OPTISON,  the  Company's  second-generation  contrast
  agent for cardiac ultrasound imaging,  received final marketing authorization by
  the European Agency for the Evaluation of Medicinal Products for use in patients
  with suspected or known cardiovascular  disease. The authorization covers all 15
  member states of the European Union.
  
           A copy of the  press  release  that the  Company  jointly  issued  with
  Mallinckrodt, Inc., on May 19, 1998, is attached to this Report as Exhibit 10.1.
  Mallinckrodt, Inc., is the Company's marketing partner for OPTISON in the United
  States and most other regions of the world.
  Signature
             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.
  
             Date:   May 22, 1998.
  
             Molecular Biosystems, Inc.
  
             By       /s/ Gerard A. Wills
                      Gerard A. Wills
                      Vice President, Finance
                        and Chief Financial Officer
  Exhibit Index
                                                                Sequentially
       Exhibit         Description                              Numbered Page
  
       10.1            Press release (May 19, 1998)                  5