Thirty one cases of acromioclavicular injuries were treated in both Kangnam Sacred Heart Hospital and Hangang Sacred Heart Hospital during the period from May 1974 to April 1981. Three cases were classified to type 2 injuries and twenty eight were type 3. Among 31 cases one of the type 2 injuries was treated with closed reduction followed by thoracobrachial cast and remaining thirty received surgical treatment. Twenty one cases were operated on by technique of Weaver and Dunn, 8 cases by modified Phemister method and one case by Stewart technique. Preperative and postoperative stress film were evaluated and cap the coracoclavicular distance were measured. In twelve complete dislocation the authors modified the original Weaver and Dunn procedure by taking a bone chip along with the acromial end of the coracoacromial ligament. This seemed to provide a strong bony fulcrum for the suture of the ligament to clavicle as well as promoting bone to bone union. The results of this modified procedure were excellent.