Four patients with primary carcinoma of the breast metastatic to the urinary bladder are described. Hematuria was present in 3 of the 4 patients. Two of the 4 women had received steroidal drugs which may have a role in the development of this unusual metastasis. This complication developed no sooner than 32 months after diagnosis of malignant breast disease and occurred shortly before death in 2 of the patients. Bladder metastasis in women with a history of breast carcinoma may be more prevalent than has previously been suspected.