Mammary hamartoma is a rare nonmalignant lesion. Only 11 cases of carcinoma associated with hamartoma have been previously described in the literature. We describe a case of infiltrating ductal carcinoma (IDC) and ductal carcinoma in situ (DCIS) associated with hamartoma in a 35-year-old woman. Mammography showed the features of a typical hamartoma with suspicious microcalcifications arising in it. The patient underwent a radical modified mastectomy. It is likely that hamartoma is a coincidental finding. The identification of suspicious microcalcifications in a typical mammographic image of a hamartoma should prompt continued examination to exclude an underlying tumor.