A retrospective study of 134 patients with Types I, II, and III acromioclavicular separations was carried out. The average followup was 6.3 years, with the longest being 19 years, and the shortest being 1 year. The mechanism of injury was a direct blow in 92% of the patients. The average age of the patients was 30.1 years, with a range from 13 to 68 years. All patients were evaluated using a standard rating system for the shoulder and humerus, the total for perfect recovery being 100. Twenty-four patients with Type I separations were immobilized 19.5 days, with a disability period of 6 weeks, and rated 94 points. Twenty-five patients with Type II separations were immobilized 27 days for the conservative groups, had a disability period of 6 weeks, and rated 90 points. Eighty-five patients with Type III acromioclavicular separations were followed. Seven patients had conservative treatment, were immobilized an average of 22 days, with a disability period of 13 weeks, and rated 82. Of those patients who underwent surgical repair, excluding Dacron graft substitution, the immobilization period was 6 weeks, with a disability period of 12 weeks, and a rating of 80. Fifty-eight patients underwent repair with double velour Dacron prosthetic substitution for the coracoclavicular ligaments, combined with distal clavicular resection in all but two patients. The average immobilization period was 1 week, with the average disability period being 3 weeks. The average rating was 96, with 24 patients rating 100. The major cause for a rating less than 100 was light to moderate pain that persisted in a few cases, which was only occasional and associated with a particular activity. One infection occurred requiring graft removal 5 months after surgery. Calcification in the area of the coracoclavicular ligaments did not affect the final rating and recurrence of deformity was not noted.