It has been postulated that vitamin E compounds (tocopherols) can retard the aging process. Therefore, changes in concentrations of tocopherols in human plasma and platelets with aging were studied. Fasting blood samples were obtained from 48 healthy male volunteers aged 24-91 years. Concentrations of the tocopherols in plasma and platelets were determined by a liquid chromatographic method. Alpha and gamma tocopherols were the major forms of vitamin E found in both plasma and platelets. The concentrations of alpha and total tocopherols in plasma did not change significantly with age. However, the plasma gamma tocopherol and the platelet alpha, gamma, and total tocopherol concentrations decreased significantly with age. The platelet to plasma ratios of tocopherol concentrations also decreased with age.