We report an unusual case of a type I Monteggia equivalent lesion in a 6-year-old girl consisting of fracture of the ulnar diaphysis and fracture of the neck of the radius without dislocation of the radial head. Manual reduction and immobilization in a plaster cast were performed. At 10 years of follow-up, the patient had regained full flexion and extension of the elbow, and nearly full pronation and supination. In the literature, this lesion has been reported only in two paediatric patients indicating that this is an extremely rare trauma.