Arthroscopic laser synovectomy consists of a mechanical abrasion of the superficial layers followed by a laser devitalization of the basal synovium. The Neodymium-YAG-laser is suitable for this purpose because of its depth of penetration in tissue and the transmission through quartz flexible fibers. In histological in-vivo-studies laser induced changes in the deep synovial layers could be verified. After a total of 50 arthroscopic laser procedures the clinical results of the first 15 laser synovectomies are analyzed in a follow-up period of 6 months. Compared to the preoperative condition the arthroscopic operation resulted in a significant improvement. A reduced hemorrhage is a specific advantage of this technique. Arthroscopic laser synovectomy is as effective as conventional open capsulosynovectomy preserving the advantages of arthroscopic surgery, a reduced morbidity, a low functional impairment and short rehabilitation periods.