Open carpal tunnel release has been the standard method of sumical treatment of carpal tunnel syndrome. Recently endoscopic carpal tunnel release has been introduced and is heing used by many authors. The advantages of this new technique are less postoperative pain, rapid restoration of power and rapid return-to-work. However many considerate authors, in spite of these advantages. insist that the inevitahle risk of neurovascular injury during the endoscopic procedure should not he underestimated. The purpose of our study is to compare the clinical results of endoscopic carpal tunnel release with those of open release. 20 open carpal tunnel releases in 16 patients and 15 endoscopic carpal tunnel reieases (single-portal technique) in 11 patients were performed hy the first author. Preoperative conditions of both groups are not different. Authors compared the clinical results between the two groups with some parameters. The overall clinical results were not different significantly hetween two groups. Rapid return-to-work(36 days in endoscopic group versus 60 days in open group) and less postoperative scar and pillar pain in endoscopic group were demonstrated. However, the major complication of one median nerve injury in endoscopic group seemed to overweigh these some benefits. We suggest that the standard operative technique for carpal tunnel syndrome should be open carpal tunnel release and more considerations should be takcn in choosing endoscopic method because of its inherent risk.