Sixty-seven Monteggia lesions occurring in adults were reviewed. A follow-up of 1 to 14 years revealed that 53.7% had good to excellent results and 46.3% had results which were fair or poor. All fractures were treated with open reduction and internal fixation. Complications were encountered in 29 cases or 43%. Delayed bone healing in 10 cases and the persistent dislocation of the radial head in 7 cases were noted. Excellent or good results were seen in type III and I, according to Bado's classification; fair or poor results in type IV and II. The results are less good when the olecranon process is fractured, especially in type Ia fractures. The overall result of this injury is abysmal. To improve the outcomes, the authors recommend dorsal plating of the ulnar fracture, avoidance of early resection of the radial head and immediate mobilization of the elbow.