Poland's syndrome is a rare congenital anomaly characterized by unilateral chest wall hypoplasia and ipsilateral hand abnormalities. It has been reported in association with various malignancies and other developmental defects. We report here the case of a 58-year-old woman with Poland's syndrome who developed breast cancer in the ipsilateral normal breast. A review of the literature reveals that two studies of breast carcinoma associated with Poland's syndrome have been reported, but this paper is the first example of a carcinoma occurring in an otherwise normal breast associated with Poland's syndrome.