Pigmented villonodular synovitis (PVNS) is a relatively rare condition. It occurs in two forms: a diffuse form involves the entire synovium and occurs in the majority of cases, and a localized form involves a discrete section of the synovium. The disorder almost always involves a single joint and the knee is most commonly affected. We report on three cases of localized PVNS that involved the patellar fat pad and synovium. Diagnostic and therapeutic arthroscopies were performed, and typical localized PVNS was found. Complete resection of the lesions was performed arthroscopically. Arthroscopy can be used as an effective diagnostic and therapeutic tool for identification and treatment of intra-articular localized PVNS of the knee.