Authors reviewed thirty-one patients treated for Monteggia frature-dislocation at the Orthopedic Surgery, Guro Hospital, Korea University, College of Medicine from September 1983 to January 1992. The results were as follows: 1. Classification of the 31 patients showed 21(68%) males and 10(32%) females, and 7(23%) patients were in the 1st decade, 8(26%) in 2nd, 7(23%) in 3rd in 4th, 6(19%) in 5th. 2. The major cause of injury were falldown in 16(52%) cases, traffic accident in 9(29%), direct trauma in 4(13%) and roller injury in 2(6%) cases. 3. According to the Bado classification(1967), there were 17(55%) cases of Type 1, 3(9%) cases of Type 2, 6(19%) cases of Type 3 and 5(16%) cases of Type 4. 4. Location of the ulnar fracture site were proximal metaphysis in 15(51%) cases, proximal 1/3 in 1 1(35%) cases, middle 1/3 in 4(13%) cases. 5. Palsies of posterior interosseous nerve were observed in 4(13%) patient, followed by full recovery. 6. Treatment for ulna fracture were open reduction and internal fixation in 22(71%) patients. The closed reductions in 9(29%) patients. Closed reductions were performed to manage children. 7. With the criteria of Bruce(1974), the results were excellent in 16(51%) cases, good in 5(16%) cases, fair in 7(23%) cases, poor in 3(10%) cases. 8. Delay of diagnosis more than 5 weeks were 5 cases. All cases were treated by open reduction and internal fixation with annular ligament reconstruction, and the results of treatments were excellent (2), good (2), fair (1) and no poor cases. In cnoclusion, we suggest that initial appropriate treatment for Monteggia fracture dislocation in both adults and children and even in delayed cases, open reduction and rigid internal fixation and annular ligament reconstruction provide satisfactory results.