The aim of present research work was to design a stable Sustained release formulation of Non- steroidal anti-inflammatory drug (NSAID). Sustained effect of NSAID is required for managing pain of some chronic ailments like rheumatoid arthritis, osteoarthritis. Diclofenac Sodium was selected as a model drug as it has biological half-life of 1-2 hours. Diclofenac Sodium was fabricated with Eudragit L-100 polymer. Five (5) different formulations of matrix tablets of Diclofenac Sodium (185 mg) were prepared using Direct compression method. All the tablets were assessed for pre-compression and post-compression characterization. Powder blend showed good flow properties as illustrated by their angle of repose, hausner ratio, compressibility index. All the physical and chemical parameters i.e. drug content, tensile strength, friability, weight variation and disintegration time was within limit and they meet the standard criteria. In-vitro drug release was carried out in phosphate buffer pH 6.8 over 12 hours. Among all the formulations F2 showed slow drug release up to 85% over a period of 12 hours and thereby exhibited a satisfactory sustained release property. Current work explored more economical and stable formulation of Sustained release technology for Diclofenac Sodium (NSAID) as it can easily be applied in pharmaceutical preparation.