PURPOSE: To analyze the clinical results of the treatment of Mason type II radial head fractures using closed reduction and K-wire internal fixation under C-arm guide by radiologically and functionally. MATERIALS AND METHODS: Between March 2001 and October 2003, 7 patients with Mason type II radial head fracture were treated by closed reduction and internal fixation using K-wires under C-arm guide. The average age of the patients was 38 (5 to 57) years old, and average duration of follow up was 20 (5 to 36) months. At last follow up, we evaluated the radiological results and functional results by classifying excellent, good, fair and poor according to functional rating system of Broberg and Morrey. RESULTS: The range of motion of the elbow at last follow up, average flexion contracture was 1.4 (0 to 10) degrees, further average flexion was 146.4 (140 to 150) degrees, average supination was 74.2 (70 to 80) degrees and average pronation was 75 (70 to 80) degrees. In the functional results, 6 cases were excellent and 1 case was good. In the radiological evaluations, the average time of union was 5 (4 to 6) weeks after the operation and no serious complication was occurred in any cases. CONCLUSION: In the treatment of Mason type II radial head fracures, closed reduction and K-wire internal fixation under C-arm guide was an effective method of treatment with satisfactory results and no complications.