A neglected Monteggia fracture can pose a significant clinical problem because of decreased range of motion of the elbow, increased cubitus valgus, progressive damage and elbow instability. Factors leading to misdiagnosis include swelling of soft tissue, overlying of bones on radiographs and lack of inclusion of the elbow on the radiograph at the ulnsr fracture. Therefore, a radiograph that includes the elbow at the ulnar fracture should be taken. A line drawn through the shaft and head of the radius into the elbow should align with the capitulum in any projection, thereby assisting in the correct diagnosis. Three cases of neglected Monteggia fracture were treated by open reduction of the radial head with repair or reconstruction of the annular ligament and osteotomy of the ulna, and satisfactory results were obtained.