Benign intraductal papilloma is a rare lesion in the male breast. The authors report the occurrence of an intraductal papilloma in a male with more than a ten-year history of phenothiazine therapy (Mellaril and Prolixin). Phenothiazines have been demonstrated to cause elevated serum prolactin levels. The literature regarding the relationship between prolactin and mammary tumors in rodents and in humans remains controversial. The occurrence of this rare male breast tumor in the setting of chronic phenothiazine therapy raises further questions as to the role of prolactin in the development of mammary tumors.