Stage IV breast cancers (Tnm classificaiton) were clinicopathologically investigated by stratification accordin to distant metastases. Of 437 female patients with primary breast cancer in the period between 1965 and 1987, 4 patients were classified to stage IV. They consisted of 26m+ and 19m-. Metastases of distant organs wer detected in 19 patients, while seven cases had the invasive lesions beyond the breast. Histology showed 14 scirrhou carcinomas, 9 solid tubular carcinomas and 3 others in m+ group, and 15 scirrhous carcinomas and 4 solid tubula carcinoma in m- group. The sites of distant metastases included the lung in one, pleura in 2, bone in 12, lung an bone in 2, and lung, bone and liver in 2 cases. Effects of therapeutic agents could not be assessed because of variou kinds of therapy. The m- group showed a significantly longer survival for postoperative 2 to 4 years, but th difference did not reach the level of statistical significance afterwards.