Teratoma of the stomach is a very rare tumor. Nearly all previously reported patients were males. We report a 4 day-old male infant, who presented with a palpable abdominal mass. A preliminary diagnosis of teratoma was made by abdominal x-ray, sonography and MR imaging. Surgery was performed and diagnosis of teratoma of the stomach was confirmed by histological examination of the tumor. Because teratoma of the stomach is always a benign neoplasm surgery is curative and no further therapy is needed.