The aim of this study was to prepare Diclofenac potassium (DP) microspheres by using Double Emulsion-solvent evaporation method with ethyl cellulose (EC) and Eudragit polymers. An attempt was made to formulate a sustained release dosage form of diclofenac potassium, to minimize frequent dosing as well as reducing or eliminating local side effects by avoiding the drug release in the upper gastro-intestinal tract Poly vinyl alcohol containing 2% (w/w) span 80 was the external phase and polymer -drug solution was the internal phase. EC and Eudragit were used to encapsulate diclofenac potassium. By using different formulation variables, six different formulations (F1, F2, F3, F4, F5, & F6) were prepared. The resulting microspheres obtained, were more spherical in shape and showed more entrapment efficiency. The size of the microspheres varied between 346-695 μm and as high as 96.24% loading efficiency for Eudragit and 82.34% for EC was obtained. In vitro release study was carried out in 0.1 N hydrochloric acid solution (pH 1.2) for first 2 hours followed by in phosphate buffer solution (pH 6.8) for next 4 hours. After first 2 hours of dissolution in 0.1 N hydrochloric acid, EC microspheres released 23% of drug and Eudragit released 7% of drug. The formulations were found to be effective in providing controlled release of drug for a longer period of time.