In briefLow back pain is one of the most common complaints of athletes, and the differential diagnosis is challenging because the cause can be biomechanical, neoplastic, infectious, developmental, or traumatic. The author reviews diagnostic steps from medical history and physical examination to the use of bone scans, myelography, and tomography. He also reviews injuries and diseases specific to the adolescent spine and urges physicians to use flexibility exercises to correct the athlete's problem while allowing sports participation to continue. Treatment goals should include pain relief and prevention of further lumbar segment injury.