Though extremely rare, teratoma must also be considered in the differential diagnosis of abdominal mass in the first year of life. The kidney is among the least frequent of the various anatomic location in which teratoma and other germ cell tumors have been reported. One of the earliest cases reported by McCurd(1934) in a 7 week old male with multiple anomalies. The intrarenal teratoma simulated nearly all of the preoperative features including the roentgenographic findings of Wilm's tumor. A histologic examination was required to reverse the clinical and operative impression. We report an anesthetic experience of a 3 month old infant with hypertension being admitted to our hospital with the chief complaint of abdominal mass, which was clinically diagnosed as Wilms' tumor. However postoperative pathologic diagnosis was found to be intrarenal teratoma.