Injury to the medial collateral ligament of the elbow (MCL) can be a career-threatening injury for an overhead athlete without appropriate diagnosis and treatment. It has been considered separately from other athletic injuries due to the unique constellation of pathology that results from repetitive overhead throwing. The past decade has witnessed tremendous gains in understanding of the complex interplay between the dynamic and static stabilizers of the athlete's elbow. Likewise, the necessity to treat these problems in a minimally invasive manner has driven the development of sophisticated techniques and instrumentation for elbow arthroscopy. MCL injuries, ulnar neuritis, valgus extension overload with osteophyte formation and posteromedial impingement, flexor pronator strain, medial epicondyle pathology, and osteochondritis dissecans (OCD) of the capitellum have all been described as sequelae of the overhead throwing motion. In addition, loose body formation, bony spur formation, and capsular contracture can all be present in conjunction with these problems or as isolated entities. Not all pathology in the thrower's elbow is amenable to arthroscopic treatment; however, the clinician must be familiar with all of these problems in order to form a comprehensive differential diagnosis for an athlete presenting with elbow pain, and he or she must be comfortable with the variety of open and arthroscopic treatments available to best serve the patient. An understanding of the anatomy and biomechanics of the thrower's elbow is critical to the care of this population. The preoperative evaluation should focus on a thorough history and physical examination, as well as on specific diagnostic imaging modalities. Arthroscopic setup, including anesthesia, patient positioning, and portal choices will be discussed. Operative techniques in the anterior and posterior compartments will be reviewed, as well as postoperative rehabilitation and surgical results. Lastly, complications will be reviewed.