Purpose: We investigated the short term results of medial deltoid ligament repair after diagnosis of chronic medial ankle instability. Materials and Methods: 262 military patients with ankle instability symptom were evaluated between May 2007 and December 2009. We diagnosed 29 chronic medial ankle instability cases with medial drive through sign under arthroscopy, radiologic findings and physical exam, treated with deltoid talo-navicular band repair using anchor suture. We used the American orthopedic foot and ankle society ankle-hindfoot score (AOFAS), visual analog scale (VAS) and ankle functional satisfactory scores were carried out. Results: 29 patients (11.1%) has chronic medial ankle instability, mean AFOAS score, VAS was improved from 65.4(range; 43-83), 6.0(range; 4-10) to 82.0(range; 60-100), 3.2(range; 1-7). Patients satisfaction were excellent 13(44.8%), good 11(37.9%) and poor 5(17.2%). Two cases was recurred and revised with allo-tendinous reconstruction. Conclusion: We underwent surgery to repair the talo-navicular ligament for chronic medial ankle instability, and about 83% of satisfactory results were obtained.