The demands that throwing Places on the vulnerable immature elbow frequently produce multiple injuries. Significant clues in the history include persistent medial elbow soreness, stiffness, and discomfort that lead to poor performance. Diagnosis involves identifying the injury sites by palpation and x-rays that pinpoint growth-plate separation or osteochondral changes. Nonoperative treatment, which can proceed if growth-plate separation at the medial apophysis is less than 3 mm, involves stretching, strengthening, sport-specific activities, and interval throwing. Prevention includes conditioning, limiting the number of pitches, and using age guidelines for learning new pitches.