OBJECTIVE To describe traumatic fracture of the medial coronoid process in dogs as a clinically distinct disease unrelated to congenital elbow dysplasia. METHODS Clinical records of dogs with acute, traumatic, unilateral lameness attributable to medial coronoid process disease were reviewed retrospectively. Clinical interpretation included findings on physical examination, orthopaedic examination, and subjective gait analysis. Radiographs of the affected and contralateral elbows were obtained and reviewed for pathology. Arthroscopy of the elbow joints was performed by one of three surgeons and findings were compared to preoperative diagnostics. Postoperative follow-up was continued for 16 weeks. RESULTS Twenty-four dogs were included in this study. All dogs in this study were free of radiographic evidence of medial coronoid pathology. All dogs were diagnosed with a single, large, displaced or non-displaced fracture of the medial coronoid process, with no other joint pathology. Dogs generally had an excellent short-term outcome following arthroscopic treatment of the fractured medial coronoid process. CONCLUSIONS Traumatic fracture of the medial coronoid process should be considered a clinical disease distinct from dysplasia-related fragmentation and should be considered as a differential diagnosis in dogs that are presented with the complaint of acute unilateral elbow discomfort or lameness, especially after concussive activities involving the forelimb. .