Purpose: We try to retrospectively analyze the clinical results of the modified Chrisman-Snook procedure for chronic ankle instability. Materials and Methods: From November 1997 to April 2006, thirty-one patients who underwent modified Chrisman-Snook procedure for chronic ankle instability were analyzed. All patients were male and the mean age was 31 years. The follow-up period averaged 48 months. We evaluated the clinical results measured by Hasegawa method. Results: Among them, there were soldiers in 11, socker players in 6, patients who weigh more 80 kg in 5. And there were 9 patients who previously underwent modified Brostrom procedure for chronic ankle instability. The clinical results were rated as excellent in 29, fair in 2 who did not cooperate with postoperative rehabilitation program. There were complications of 2 cases of irritation of the sural nerve and recurrence respectively, 1 case of wound problem. Conclusion: Our results show that the modified Chrisman-Snook procedure is effective treatment method for patients with high-performance athlete/soldier or failed modified Brostrom procedure.