Eight patients with localized pigmented villonodular synovitis (LPVNS) of the knee were treated with arthroscopic and open techniques, with diagnosis confirmed by histological examination. Average patient age was 29 years (range: 13-50 years). At arthroscopy, all lesions except one were in the anterior compartment of the involved knee. Treatment consisted of complete local excision with partial synovectomy. This procedure was completed arthroscopically in seven patients. No recurrence was reported at average 24-month follow-up (range: 12-33 months). Arthroscopy is a valuable tool in the diagnosis and treatment of LPVNS.