There has been considerable controversy as to the method of treatment of acromioclavicular joint especially in grade III injury. We treated 27 cases of the complete dislocation of acromioclavicular dislocation with operative method(15 cases) and conservative method(12 cases) from October 1989 to November 1995. The purpose of this study is to compare the clinical and radiological result of two treatment method. The average follow up period was thirty nine months and the result as follows. 1. Of the 27 cases, there was 18 male and 9 female patients, and peak incidence was in 3rd and 4th decades(51%). 2. The most common causes of the injury was traffic atcident(49%). 3. The functional results were similiar to all treatment modalities, and coracoclavicular interval ratio was well manintained regardless of treatment. 4. Complication rate was more lower in the group of conservative treatment. 5. The conservative treatment was proven to be a valuable method for acromioclavicular dis- location except in a few situations.