As knowledge grows about breast cancer in men, it becomes apparent that the disease is strikingly similar to that seen in women. Although rare, as is cancer in most vestigial organs, all indications are that it shares a common etiology and a similar natural history with breast cancer in females and that apparent differences between the diseases in the two sexes are minor or illusory. The poor prognosis of men in the past promises to yield to better public and professional education about the value of prompt recognition and treatment. Fortunately, the lessons learned from treatment of women are also applicable to men, and in comparable stages men prove equally curable.