Elbow fractures are not uncommon in children, and some are associated with neurovascular injuries. Having a nerve injury in an elbow fracture without dislocation is rare and was not described in the literature. Here, we have reported probably the first case of an ulnar nerve injury in an elbow fracture without dislocation. A 9-year-old female presented to the emergency department after falling off a monkey bar. She had a painful, swollen and tender right elbow with no history or clinical signs of an elbow dislocation but had complete ulnar nerve palsy. She was managed initially with analgesia and plaster application and was taken directly to the operating theatre. Examination under anaesthesia revealed no elbow joint instability. The ulnar nerve was found entrapped between the trochlea and proximal ulna, intra-articularly. The medial epicondyle was also found avulsed from the humerus, with an incarcerated medial epicondylar fragment in the elbow joint.