In the present study, Mefenamic acid 200 mg controlled release matrices were prepared by direct compression and in vitro drug dissolution studies were performed to find out the drug release rate and patterns. Methocel was used as rate controlling polymer. Also the effect of several co-excipients was investigated on the drug release rates during in vitro dissolution studies. Polymer Methocel was used as a rate controlling polymer and was formulated with the drug at 4 different D: P ratios. Phosphate buffer pH 7.2 was used as dissolution medium using PharmaTest dissolution apparatus. Several kinetic models were applied to the dissolution profiles to determine the drug release kinetics. Dissolution equivalency evaluation was performed using f2 similarity factor.