Background Elbow injury is common in boxing, but it has not been reported in the literature. The onset is often a hyperextension trauma caused by a missed hit. Clinically the boxers complain of pain, stiffness, and an extension deficit. Purpose To evaluate the pathogenesis, diagnostic approach, and arthroscopic treatment of elbow injury in boxers, and to compare these with other sports-related elbow injuries. Study Design Case series; Level of evidence, 4. Methods Between 2003 and 2005, a group of 5 professional boxers received a diagnosis of posterior elbow impingement. An arthroscopic debridement was performed. All patients were evaluated preoperatively and 1 year postoperatively with the Hospital for Special Surgery Elbow Assessment Scale. Results An arthroscopic partial resection of the posterior olecranon tip was performed, and osteophytes and fibrous tissue were removed in this area. Loose bodies were removed from the elbow in 3 patients. They were present in the posterior compartment in 2 patients and the anterior compartment in 1. The Hospital for Special Surgery score showed satisfactory to good improvement after 1 year in all 5 cases. They all showed a normal function at follow-up and had a full return to their sports activities. In contrast with the valgus extension overload syndrome, our patients did not show any signs of concomitant ulnar collateral ligament injury. Conclusion Posterolateral elbow impingement in boxers is caused by hyperextension trauma. Concomitant medial elbow instability was not present. Standard arthroscopic debridement showed good results.