Purpose: To evaluate the result of arthroscopic modified Brostrom procedure with suture anchor for chronic lateral ankle instability. Materials and Methods: Fifty-two patients with chronic lateral ankle instability were analyzed, who underwent arthroscopic modified Brostrom procedure between December 2010 and May 2012. Clinical evaluation was performed using AOFAS scroring and Sefton grading system. Results: The average AOFAS hind foot score increased from preoperative 61.9 to 88.8 at the last follow up. There were 35 excellent, 9 good, 4 fair, 4 poor results according to Sefton grading system. For one patient, lateral ankle instability recurred. Conclusion: Arthroscopic modified Brostrom procedure is considered to be an effective and satisfactory technique.