Variations of epidermal zinc concentration with aging were studied by measuring zinc levels in the epidermis of two groups of healthy subjects: group A aged less than 35 years; group B aged more than 65 years. The epidermis was obtained from a suction blister, and zinc levels measurements were performed by absorption spectrophotometry. There was a significant decrease (p less than 0.01) of epidermal zinc concentration with aging, and zinc contents of the epidermis were the same in men and women. On the other hand, no significant difference was found in zinc blister fluid levels between the two groups, confirming the absence of relationship between plasma zinc and epidermal zinc. The decrease of epidermal zinc concentrations observed in elderly subjects might be due to a decrease of enzyme activities in the epidermis induced by aging; conversely, a low epidermal zinc level might induce, by itself, a fall in enzyme activities. Thus, zinc might play an important role in the development of alterations in keratinocytes with aging.