Metformin hydrochloride (MET) is an oral hypoglycemic agent which improves glucose tolerance in patients with type 2 diabetes and diminishes basal plasma levels of glucose. The aim of this study was to develop and optimize MET matrix tablets for SR application. The SR matrix tablet of MET was prepared by wet granulation technique using Polyvinyl pyrrolidone K30 and hydroxyl propyl methylcellulose of different viscosity grades (HPMC K4M, HPMC K15M, and HPMC K100M). The influence of varying the polymer ratios was evaluated. The excipients used in this study did not modify physicochemical properties of the drug. MET has relatively short plasma half-life, low absolute bioavailability. The need for the administration 2 to 3 times a day when larger doses are required can decrease patient fulfillment. SR formulation that would maintain plasma level for 8-12 h might be sufficient for daily dosing of MET. SR products are needed for MET to prolong its duration of action and to improve patient compliances. The development of oral sustained release systems has been a challenge to formulation scientists due to their inability to restrain and localize the system at targeted areas of the gastrointestinal tract. From all the formulation trial batches, formulation F3 shows the best results. It has been observed that HPMC K100M alone cannot give satisfactory drug release profile but the blend of HPMC K100M and Polyvinyl pyrrolidone K30 together give the best drug release kinetics. Thus, sustained release matrix tablets of metformin hydrochloride can be expected to reduce the frequency of administration and decrease the dose dependent side effects. Keywords: Metformin hydrochloride, SR matrix tablet, HPMC K100M, Wet granulation technique