A retrospective chart review was conducted of men with the diagnosis of carcinoma of the breast seen at this institution between January 1967 and March 1981. Eighty-nine patients were available for analysis. These cases were evaluated to determine whether the natural history of this disease was similar to that of women with carcinoma of the breast and to identify prognostic variables in carcinoma of the male breast. The results of this review would suggest that many similarities exist between breast cancer in women and in men. The most common presenting symptom is a lump, the patterns of recurrence are similar for both men and women, and survival is determined by initial T stage and the presence or absence of nodes. Local postoperative radiotherapy does not influence overall survival in male breast cancer but does decrease the incidence of chest wall recurrence. Survival after recurrence is short and is similar to that observed for women with recurrent carcinoma of the breast. The differences observed in the present series were that the median age at presentation of 63.6 years is somewhat greater than that usually observed in women; no cases of lobular carcinoma were observed; and in the 44 patients who developed recurrences to date, none had evidence of liver metastases as the initial site of recurrence. In most respects the natural history of male breast cancer is similar to that of carcinoma of the breast in women. Since carcinoma of the male breast is a relatively rare malignancy. it is reasonable to recommend management of this disease be based on the greater base of knowledge available for carcinoma of the female breast.