In this study, poly(ethylene glycol-diacrylate) (PEG-DA) hydrogels with two different concentrations, 30% and 50% w/w, were prepared by free radical polymerization method. Ethylene glycol dimethacrylate (EGDMA) and 2,2-dimethoxy-2-phenyl-acetophenone (DMPA) were used as cross-linking agent and photoinitiator, respectively. The model drug ketoprofen (KP) was incorporated into the hydrogel during photopolymerization and its release kinetics was tested spectrophotometrically at 256 nm in different buffer solutions of pH 7.5, 4.5, and 1.2. The results showed that the release of KP strongly depends on the dissolution of drug, initial polymer concentration, and the pH of the release medium. All of the obtained results were evaluated kinetically by first order and zero order, Higuchi and Hixon-Crowell kinetic models. The release mechanism was found to obey Higuchi and first order kinetics when the release data of the formulations were applied to the models in the different pH mediums.