We have reviewed 40 patients of acute acromioclavicular dislocation all treated by several operative procedure from January 1990 to July 1996. After about l2 months follow up period, we analyzed the relationship between the type of operation and the clinical results. Several operative methods were demonstrated till now, but 4 techniques or their combinations are commonly used. Those are fixation of acromioclavicular joint, fixation of coracoclavicular ligament, resection of distal end of clavicle and dynamic muscle transfer. Modified Phemister technique, modified Phemister technique with coracoclavicular fixation and modified Bosworth technique were used with or without repairment of coracoclavicular ligament at our hospital. Modified Phemister technique showed less good results than those of other techniques especially when repair of the coracoclavicular ligament was not made, and the repair of the coracoclavicular ligaments or fixation of the coracoclavicular joint is an important factor affecting the final results.