Sebaceous gland secretion was measured in 649 male and female subjects, of whom 67 (10.3 per cent) were black. No consistent difference in sebaceous gland activity was found between black and white skin. As sebum is an integral etiologic factor in acne, these findings are consistent with the clinical impression and with epidemiologic data, albeit scant, that the incidence of acne vulgaris in the black population differs little, if at all, from the incidence in the white population.