Patellofemoral pain syndrome (PFPS) is one of the most common causes of anterior knee pain encountered in the outpatient setting in adolescents and adults younger than 60 years. The incidence in the United States is between 3% and 6%. The cardinal feature of PFPS is pain in or around the anterior knee that intensifies when the knee is flexed during weight-bearing activities. The pain of PFPS often worsens with prolonged sitting or descending stairs. The most sensitive physical examination finding is pain with squatting. Examining a patient's gait, posture, and footwear can help identify contributing causes. Plain radiographs of the knee are not necessary for the diagnosis of PFPS but can exclude other diagnoses, such as osteoarthritis, patellar fracture, and osteochondritis. If conservative treatment measures are unsuccessful, plain radiography is recommended. Treatment of PFPS includes rest, a short course of nonsteroidal anti-inflammatory drugs, and physical therapy directed at strengthening the hip flexor, trunk, and knee muscle groups. Patellar kinesiotaping may provide additional short-term pain relief; however, evidence is insufficient to support its routine use. Surgery is considered a last resort.