60 patients with de Quervain's tenosynovitis were randomized to compare the effect of endoscopic release of the first dorsal compartment to open release. Follow-up was conducted for 24 weeks postoperatively. Both procedures significantly improved pain and function over the first 24 weeks after surgery. Pain and disability was significantly better after 12 weeks in patients who were treated with the endoscopic procedure, but significance was not maintained at 24 weeks. The endoscopic procedure was also associated with fewer cases of superficial radial nerve injury, and with higher patient satisfaction with the appearance of the scar.