Although physical therapy forms the mainstay of nonoperative management for patellofemoral pain, its efficacy has not been established.Significantly more pain relief will be achieved from a 6-week regimen of physical therapy than from placebo treatment.Multicenter, randomized, double-blinded, placebo-controlled trial.Seventy-one subjects, 40 years of age or younger with patellofemoral pain of 1 month or longer, were randomly allocated to a physical therapy or placebo group. A standardized treatment program consisted of six treatment sessions, once weekly. Physical therapy included quadriceps muscle retraining, patellofemoral joint mobilization, and patellar taping, and daily home exercises. The placebo treatment consisted of sham ultrasound, light application of a nontherapeutic gel, and placebo taping.Sixty-seven participants completed the trial. The physical therapy group (N = 33) demonstrated significantly greater reduction in the scores for average pain, worst pain, and disability than did the placebo group (N = 34).A six-treatment, 6-week physical therapy regimen is efficacious for alleviation of patellofemoral pain.