The maximum achievable life span of animals appears to be species specific and has been suggested to be related to DNA damage. The rate of accumulation of such damage may be altered by repair mechanisms. The excision repair of ultraviolet (UV)-induced DNA damage in fibroblasts has been shown to correlate well with maximum achievable life spans in a number of placental mammals. Evidence is presented here that the correlation between life span and UV-induced excision repair of DNA damage holds within a more closely related group, the primates, in not only primary fibroblasts cell cultures, but also nonstimulated lymphocytes.