Metformin hydrochloride is a hypoglycemic agent used for the treatment of non-insulin dependent Diabetes mellitus. It is a BCS class III drug having high solubility and poor permeability. Plasma half life ranges from 1.5 to 3 hours and oral bioavailability is 50 to 60 %. Hence require frequent oral administration for adequate treatment of Diabetes. In order to extend the gastric retention time, oral sustained release dosage form was develop in the form of microspheres using different polymers (sodium CMC, HPMC K100M). All the formulations were evaluated for in-vitro dissolution, entrapment efficiency, and percentage buoyancy. Metformin hydrochloride microspheres of formulation F-4 was optimized on the basis of in-vitro drug release pattern, entrapment efficiency, percentage buoyancy. The percentage yield of optimized formulation was 72%, entrapment efficiency was 70.56%, percentage buoyancy was 86% and the cumulative percentage drug release after 11 hours was found to be 90%. The optimized formulation was tested for its stability for 6 months as per ICH guidelines and the formulation found tom be stable during the test period. Keywords: Hypoglycemic agent, Diabetes mellitus, Entrapment efficiency, Microspheres.