Exhibit 10.3

 
FIFTH AMENDMENT OF SECURITY AGREEMENT

This Fifth Amendment of Security Agreement (“Fifth Amendment”) is made as of
April 15, 2009 by BioTime, Inc., as the “Debtor,” in favor and for the benefit
of each “Secured Party,” and amends that certain Third Amended and Restated
Security Agreement, March 31, 2008, as amended by that certain Fourth Amendment
of Security Agreement.

1.           “Security Agreement” means the Third Amended and Restated Security
Agreement, March 31, 2008, as amended by the Fourth Amendment of Security
Agreement and this Fifth Amendment.

2.           “Credit Agreement” means that certain Third Amended and Restated
Revolving Line of Credit Agreement, dated March 31, 2008, as amended by the
Fourth Amendment of Revolving Line of Credit Agreement and the Fifth Amendment
of Revolving Line of Credit Agreement.

3.           “Secured Party” means, individually and collectively, each person
who has executed the Credit Agreement as a Lender.

4.           “Note” has the meaning ascribed in the Credit Agreement.

5.           Except as amended or modified by this Fifth Amendment, all
provisions of the Security Agreement in effect prior to the date of this Fifth
Amendment remain in effect.

DEBTOR

BIOTIME, INC.

By:       /s/ Steven A. Seinberg          
                                                                    
Chief Financial Officer

By:       /s/ Judith Segall                
                                                                     
Secretary