Eighty-seven patients with recurrent breast cancer after mastectomy were analyzed for patterns of recurrence and methods of detection. After an average disease-free interval of 30 months, 38% developed osseous metastases, 16% recurred locally, 10% had local plus systemic disease, 10% showed pulmonary metastases and the remainder were distributed among liver, brain, and remaining breast disease. In 79 patients recurrence was heralded by symptoms. Physical examination in five asymptomatic patients revealed local or supraclavicular recurrence. In only three asymptomatic patients was recurrence documented by "routine" chest x-rays (in two), or liver enzymes/liver scan (in one). No asymptomatic disease was found by bone scan. It is concluded that periodic history, physical examination, and chest x-rays are the most important components in the follow-up of breast cancer patients. Radioisotope scans and other radiographs are valuable in confirming symptomatic disease and detecting additional diseases, but cannot be recommended routinely in the asymptomatic patient because of low yield and cost.