Inappropriate treatment of the injury of the lateral collateral ligaments of the ankle produce residual instability, which causes serious disability. There is considerable divergence of opinion as to whether fresh rupture of the lateral ligaments of the ankle are best treated by conservative or opreative method. We have conducted a trial to analyze thirty patients, who were treated by immediate open surgical rupair of rupture of the lateral ligaments of the ankle between April 1991 and February 1992. The results were as follows: 1. All patients were active, young men, Injuries to left ankle were three times more than right side. The most common cause of injury is occurred during sports, especially association football. 2. The decision to operate was based on 1)Talar tilt angle of the injured ankle measures 8-10 degrees more than that of the stress uninjured ankle. 2)A positive arthrogram showing contrast leakage into peroneal tendon she-aths & anterolateral aspect of the lateral malleolus. 3. Diagnostic accuracy rate of arthrography is 94.5%, stress radiography 61.1 %. Arthrography is more reliable than stress radiography in the diagnosis of acute injuries to the lateral ligament of the ankle. 4. At operation, isolated rupture of anterior talofibular ligament was in 5 cases, isolated rupture of middle calcaneofibular ligament in 3 cases, concomittant ruptures of anterior talofibular and middle calcaneofibular ligements in 22 cases. 5. Location of tears of anterior talofibular ligament was mostly mid-portion, middle calcaneofibular ligament in mid-portion or distal portion. 6. On radiologic results, average angle of talar tilt was 14.4° preoperatively, 5.2 preoperatively. There was correction of talar tilt angle of average 9.2°. 7. Clinical results of treatment were excellent in 9 patients, good in 6 patients, fair in 4 patients, poor in 2 patients by authors rating system. The satisfactory result was achieved in 15 patients(71.4%). 8. Postoperative complication was reduced mobility in 4 cases, functional instability 1 case, neuroma in operation scar in 2 cases, minor sensory loss in 4 cases. 9. Primary surgical repair gave good results in the aspect of radiologic & fun ctional instability, but clinical results were not satisfactory, due to high incidence of postoperative complication.