Kinetic studies of supercritical extraction experiments to recover organic material from Turkish Göynük and U.S. Western Reference oil shales were carried out. Solubilization curves of both shales were studied in two regions; a sharply rising part reaching an intermediate state solubilization and a part where gradual changes were observed at extended periods. Organic material recovered from demineralized oil shales when the intermediate state was attained was much lower than the percentage of organic material recovered from the original oil shale. Kinetic analysis indicated that the interaction in the first region produced primary products from the organic material of the shale while the interaction in the second region contained secondary reactions among the primary products obtained before the intermediate state was attained.