We have been applying endoscope-assisted minilaparotomy (endoscopic minilaparotomy) to retroperitoneal operations with favorable outcomes. Here, endoscopic minilaparotomy through a single flank incision (4-7 cm) was performed in three cases of incidentally discovered retroperitoneal Schwannoma. Resection of the tumor was successfully completed. The postoperative course was uneventful. Wound pain was mild and full oral feeding and walk were resumed the day following operation. It is concluded that endoscopic minilaparotomy is applicable to retroperitoneal Schwannoma with excellent postoperative recovery.