Nine men with advanced carcinoma of the breast were evaluated after orchiectomy at the National Institutes of Health over 19 years. Of patients followed for greater than one year, five had complete remissions, one had a partial remission, and two patients did not respond to orchiectomy. The average disease-free interval was 20 months; the average survival from the time of orchiectomy in those who responded was 55.8 months and in nonresponders was 26.7 months. Orchiectomy appears to be a safe and effective way to produce an objective response and prolong survival in over 50 percent of men with advanced breast cancer.