Ketoprofen powder was encapsulated with Eudragit RL/RS polymer solutions in isopropanol-acetone 1:1, using a simple and rapid method. Microcapsules were prepared using Eudragit solutions with different RL/RS ratios. The encapsulation process produces free-flowing microcapsules with good drug content and marked decrease in dissolution rate. The retardation in release profile of ketoprofen from microcapsules was a function of the polymer ratio employed in the encapsulation process. In vitro release of ketoprofen from microcapsules either filled in gelatin capsules or compressed into tablets, using calcium sulphate as diluent, confirmed the efficiency of the encapsulation process for preparing prolonged release medication. A capsule formulation with optimum sustained-release profile was suggested.