Arthroscopic debridement has been used to treat patients with degenerative knee osteoarthritis, although there is sometimes conflicting evidence documenting its efficacy. This study evaluates the success of arthroscopic debridement in elderly patients with grade III and IV chondromalacia of the knee as measured by patient satisfaction and the need for additional surgery. From December 1998 to August 2001, a total of 102 consecutive cases of knee arthroscopy in 99 patients > 60 years were performed. Average follow-up was 34 months (range: 7-104 months). Patients were asked about their satisfaction using a visual analog scale, and the presence of meniscal lesions during arthroscopy and the treatment for these lesions were evaluated. Knees also were assessed for articular surface degeneration using Outerbridge's classification for chondromalacia. The need for and type of additional surgery was evaluated. During arthroscopy, meniscal lesions requiring a partial meniscectomy were found in 95 knees. Chondromalacia was found in 92 knees; 53 knees had grade I or II chondromalacia and 39 knees had grade III or IV chondromalacia. Additional surgery was performed in 17 knees. Mean patient satisfaction score was 73 (range: 50-100) in the 39 knees with grade III or IV chondromalacia after arthroscopic debridement was performed. These findings suggest arthroscopic debridement in elderly patients has a place in the treatment algorithm for grade III or IV chondromalacia of the knee.