Breast cancer in men is a rare and understudied disease. Until recently, prospective studies and clinical trials on breast cancer treatments often excluded men. Treatment recommendations were generally extrapolated from the results of clinical trials that included only women. Significant efforts have been made to better understand the biological characteristics, the most effective treatments, and the outcomes of breast cancer in men, as well as to identify clinically relevant differences of this disease. This article reviews the current data on the epidemiology, pathological and clinical characteristics, as well as the treatment of breast cancer in men.