PURPOSE: Breast cancer in male is uncommon, accounting for approximately 1% of all breast cancer and less than 1.5% of all the malignant neoplasms in males. The information concerned with the treatment of male breast cancer is limited. The objective of this study is to evaluate the histopathologic characteristics and clinical outcome of male breast cancer patients. METHODS: We retrospectively analyzed the medical record of 17 male breast cancer patients who had been operated on Seoul National University Hospital between 1996 and 2006. RESULTS: The peak age of incidence was the 6th decade and the mean age of the patients was 56.2 yr. The most common symptom was a palpable mass and the mean duration of symptoms was 13 months. Fifty-three percent of the patients were stage 0 or I. Mastectomy was performed in 15 cases and lumpectomy was performed in 2 cases. Twelve patients received adjuvant hormonal therapy. The median duration of follow up was 28 months. Of the two patients with distant relapse, one patient died due to multiple metastasis and the other patient is still alive. The other patients are still alive without any evidence of metastasis or recurrence. CONCLUSION: Active diagnosis, appropriate treatments (surgery and adjuvant therapy) and close follow up are necessary for male patients who have a palpable mass in their breast.