Purpose: To analyze the clinical and radiological feature of Os subfibulare and to evaluate the results after anatomical reduction and internal fixation with bone graft for Os subfibulare. Materials and Methods: Forty-two cases, which underwent anatomic reduction and bone graft for Os subfibulare from October 1998 to September 2004 were reviewed. We analysed preopertive symptoms and onset of symptoms and radiologically measured the size and amounts of displacement of Os subfibulare under the inversion stress. Postoperatively we evaluated the clinical results measured by Hasegawa method and evidence of union. Results: Preoperatively there were only pain around the lateral malleolus in 16 cases, only instability of ankle joint in 3 cases, and pain and instability in 23 cases. The age of symptom onset averaged 23 years(range, 13-38 years). Radiographically Os sufibulare anteriorly located from lateral malleolus were in 40 cases, posteriorly situated in 2 cases. The size of Os subfibulare ranged from $1{ imes}4;mm$ to $8{ imes}17;mm$. In 22 cases of inversion stress view, displacement of the Os sbufibulare averaged $1.5{pm}1.1;mm$ (0 to 5 mm). The postoperative clinical results were excellent in 41 cases, poor in 1 case. There were complications of 1 case of irritation of sural nerve, 1 case of nonunion. Conclusion: Anatomic reduction and bone graft is effective treatment method for symptomatic Os subfibulare.