A case of extragenital choriocarcinoma which produces human chorionic gonadotropin (HCG) in the small intestine of a 48-yr-old Japanese women is reported. Only seven such cases have been reported. The patient complained of postprandial upper abdominal pain and vomiting of 5 months' duration. Nine years before, right upper lobectomy was performed because of lung undifferentiated carcinoma. Double-contrast examination of the small intestine showed irregular ulceration in the lower jejunum. Celiac angiography demonstrated a hypervascular tumor stain in the branch of the jejunal artery. The serum HCG level was elevated. Gynecological examination revealed nothing abnormal. A small intestinal neoplasm was diagnosed, and a partial resection of the jejunum was performed. Endoscopy on the operating table showed a large, irregularly shaped sessile ulcer. Histologically the tumor was diagnosed as choriocarcinoma, composed of syncytiotrophoblastic cells and cytotrophoblastic cells. Immunohistochemical staining for HCG was positive. No metastasis was present. Although extragenital choriocarcinoma in the small intestine is rare, it should be included in the differential diagnosis of small intestinal neoplasm.