The usefulness of a propionylated paper chromatography to the identification of various insoluble organic antioxidants in rubber vulcanizates was studied. Purified commercial antioxidants and commercially mixed antioxidants could be identified by the propionylated paper chromatography. Antioxidants were identified by the propionylated paper chromatography from acetone extract of pure gum vulcanizates, which were either unaged or aged in Geer-Oven. The $R_f$ values from acetone extracts of vulcanizates were a little lower than those purified samples, but the colours and shapes of the spots support the identification. No spot could be obtained by the method from the aged vulcanizate containing antioxidant 200 (2,6 Di-tert-butyl-p-cresol). This indicates that the antioxidant was converted or decomposed to other compound after aging. It was concluded from the above results that the propionylated paper chromatography is useful to identify the antioxidants from vulcanizates and presents a key for elucidating the mechanism of the inhibition.