Traumatic afflication of the elbow are so common in both adults and children that the frequency of elbow dislocation is in second to that of the shoulder. Its treatment is so standardized and its complications are well recognized. But there are some differences in biomechsnics of elbow structure of children and adult. We had analized clinically 68 cases of acute dislocation of elbow joint who were treated at Orthopedic Department, medical College of Yon Sei University. The results were as follows 1. The most prevalent age were 4–7 years old in children snd 26–35 years old in sdult. 2. The major mode of injury was slip down accident. 3. The most common type was posterior dislocation. 4. Accessory fractures were more common in child and associated injuries were more common in adult. 5. Good results were obtained from closed reduction and long arm cast immobilization. 6. Immobilization period was shorter in child even though in cases combined with accessory fracture. 7. There were few limitation of motion in children which were immobilized within 3 weeks and in adult which were immobilized within 1 week. But the more prolonged immobilization period, the severe limitation of motion was note. 8. There were less complications in child. 9. The most common mode of limitation of motion was extension.