Poland's syndrome, a rare congenital anomaly characterized by pectoralis muscle defect and ipsilateral hand abnormalities, has been reported in association with various malignancies. Gastric cancer associated with Poland's syndrome has not been described previously. To our knowledge, the case of the 21-year-old man we describe herein represents the first report of Poland's syndrome associated with gastric cancer. Although previously there was no certain evidence that linked Poland's syndrome and cancer, elucidating the molecular mechanisms that cause this syndrome may further clarify the relationship between Poland's syndrome and malignancies. At least, these associations confirm the relationship between Poland's syndrome and malignancies, and require oncologic awareness.