D,L-3-Methylglycolide (MG) was synthesized via two step reactions with a good yield (42%). It was successfully polymerized in bulk with stannous octoate as a catalyst; at 110 degreesC. The effects of the polymerization time and catalyst concentration on the molecular weight and monomer conversion were studied. Poly(D,L-lactic acid-co-glycolic acid) (D,L-PLGA50; 50/50 mol/mol) copolymers were successfully synthesized from the homopolymerization of MG with high polymerization rates and high monomer conversions under moderate polymerization conditions. H-1 NMR spectroscopy indicated that the bulk ring-opening polymerization of MG conformed to the coordination-insertion mechanism. C-13 NMR spectra of D,L-PLGA50 copolymers obtained under different experimental conditions revealed that the copolymers had alternating structures of lactyl and glycolyl.