When chondromalacia patellae is caused by lateral capsular and retinacular tightness, subcutaneous lateral release affords relief of pain. The operation, performed at the time of arthroscopy, causes minimal morbidity, and it is advantageous when cosmetics are of concern. Range-of-motion exercises are begun on the second postoperative day to keep the retinaculum open. In the postoperative examination of 25 knees at 24 to 45 months in 15 patients, there were 20 excellent and five good results; none was made worse. There were two postoperative hemarthroses. The procedure is most effective in the carefully selected patient with demonstrable tightness of the lateral capsule and retinaculum. Abnormal attachments of the iliotibial band and synovial plicae are also significant in the etiology of this syndrome.