Serine/glycolic acid-based biodegradable polymers have been prepared by ring-opening homopolymerization of 3-( O-benzyl)-L-serinylmorpholine-2,5-dione, and ring-opening copolymerization of the morpholine-2,5-dione derivative and L-lactide / 1caprolactone. The homopolymerization was carried out in the melt at 165ЊC for 3 min using stannous octanoate as the initiator and continued at lower reaction temperatures (130-150ЊC) for 48 h, using a molar ratio of monomer and initiator of 1000 yielded a polymer of M n Å 4000. The polymer prepared by homopolymerization of the morpholine-2,5-dione derivative was composed of alternating protected serine and glycolic acid residues. Random copolymers of serine and glycolic acid and L-lactic acid/ 1-caprolactone were synthesized by copolymerization reaction of 3-(O-benzyl)-L-serinylmorpholine-2,5-dione and lactide or 1-caprolactone in the melt at 165ЊC for 3 min and further reaction at 130ЊC using stannous octanoate as an initiator. The polymers were deprotected and functionalized through the side chain hydroxyl group of serine residues with an acrylate moiety for applications in injectable drug delivery, cell encapsulation.