We report a case of a secretory carcinoma of the breast in a 72-year-old woman with a long history of a left breast mass. Rapid growth and skin invasion of the tumor was noticed three months before a radical mastectomy was performed and a lung metastasis was found one month after the operation. A metastasis to the axillary nodes was noted in 6 of 9 resected specimens and a receptor assay of the estrogen and progesterone proved to be negative. This patient is the oldest case of a secretory carcinoma of the breast reported in Japan.