Seventeen cases of abdominal teratoma were studied retrospectively. These patients had been diagnosed at Cathay General Hospital from 1978 to 1993. The male to female ratio was 9:8, the range of age at diagnosis was from 2 days to 13 years. The chief complaints were palpable abdominal mass in 13 patients (76%) and abdominal distention in 7 (41%). Fifteen teratomas were located in the retroperitonium; also, 1 of the 17 had gastric teratoma and another, a tumor originating from an undescended testes. The tumors were resected in all patients. Postoperative courses were smooth except for one patient, who died suddenly on the day following surgery. No further specific management was needed because the pathologic findings were all benign in nature. Ultrasonography is of benefit in locating, as well as diagnosing, abdominal teratoma. Surgical excision is curative for the majority of cases. Long term follow-up is necessary, in consideration of the rare chance of recurrence.