We report herein a rare case of invasive ductal carcinoma of the breast associated with Poland's syndrome. The patient was a 59-year-old woman who was referred to our department after a nodule had been found in the upper outer portion of the left breast by a breast cancer screening program. On physical examination, marked hypoplasia of the right breast and upper limb was noted. Preoperative computed tomography also revealed a defect in the right pectoralis muscles. A quadrantectomy of the left breast with lymphadenectomy was subsequently performed and pathological examination of the resected specimen showed invasive ductal carcinoma. Her medical history revealed that her mother had attempted to abort the pregnancy around the fifth week of her gestation. The present case suggests that such an event during gestational development may be associated with congenital anomalies predisposing to malignant disorders.