Hexachlorophene (HCP) was tested for carcinogenicity in lifetime feeding studies in male Sprague--Dawley rats that were fed on a protein- and vitamin-deficient diet and in C57B1 and XVII/G mice that received the chemical incorporated into a complete diet. After 2 years, no significant carcinogenic effects were observed in these animals. In XVII/G mice injected subcutaneously at birth or receiving HCP via the mother's milk, the incidence of tumors was not statistically increased. No carcinogenic effect was observed in (C57B1 X C3H) F1 hybrid mice that received HCP transplacentally.