Acromioclavicular joint injuries are recently increased, but there are still controversies as to the proper choice of treatment. We treated thirty cases of acromioclavicular injuries, among these, twenty five cases were done by operative method and five cases conservatively from August 1979 to June 1988. The results were as follows, 1. The injuries were composed of one case of Type 1, 7 cases of Type 2 and 22 cases of Type 3. 2. The result of conservative treatment consisted of 2 cases of good, 1 case of fair and 2 cases of poor. 3. The final outcome of operative method was better than that of conservative one, which consisted of 16 cases of good and 9 cases of fair. 4. The cause of fair results in operative method was thought to residual lexity of the repaired coracoclavicular ligament. 5. The key point of operative treatment in acromioclavicular separation was firm and strong reconstruction of the coracoclavicular ligament. 6. Modified method of coracoclavicular ligament reconstruction using coracoacromial ligament with bone block has been tried.