Ketoprofen is a potent non-steroidal anti-inflammatory,analgesic, and antipyretic drug used for treatment of variousrheumatic diseases and painful conditions. It is rapidly absorbedregardless the route of administration. Its half life is only 1-2 hrsafter oral administration. The aim of this work was to formulatesome controlled release oral dosage forms containing ketoprofen.Cellulose acetate was chosen for this purpose. Ketoprofen-celluloseacetate microcapsules were prepared by solvent evaporationtechnique. Polyvinyl alcohol was used as an emulsifier. Theprepared microcapsules were evaluated in terms of their releaseand surface characteristics. Also, the anti-inflammatory activity ofketoprofen was evaluated using the carrageenan-induced rat's pawedema method. The release of ketoprofen from the microcapsuleswas pH dependant and decreased by increasing the polymercontent and by increasing the organic phase volume. The particlesize of the produced microcapsules was decreased by increasingthe volume of organic phase, whereas it was increased byincreasing the polymer content. In conclusion, these resultssuggested that microencapsulation of ketoprofen using celluloseacetate could be a useful approach for controlled release of thedrug.