Objective To investigate the effectiveness of lateral closing wedge osteotomy for treatment of traumatic cubitus varus deformity in children. Methods Between July 1996 and June 2010, 20 cases of traumatic cubitus varus deformity after humeral supracondylar fracture were treated by lateral closing wedge osteotomy. There were 13 boys and 7 girls, aged from 7 to 14 years (mean, 10.6 years). The left elbow was involved in 12 cases and right elbow in 8 cases. Thirteencases had received closed reduction, percutaneous Kirschner wire fixation, and external fixation in other hospital, and 7 cases misdiagnosed as elbow luxation and soft tissue injury had given external fixation. Cubitus varus deformity occurred at 2-12 years after injury. Preoperatively, the elbow range of motion (ROM) in flexion and extension was 100-150° (mean, 133.0°) and 0-24° (mean, 11.7°), respectively. The angle of cubitus varus deformity was 20-50° (mean, 32.1°). Results All incisions healed by first intention, and no related complication occurred. A total of 17 patients were followed up 1-14 years (mean, 5 years). X-ray films revealed that bone union was achieved in all cases within 5-8 weeks after operation (mean, 6 weeks). The deformity of cubitus varus was corrected in all cases. At last follow-up, the elbow ROM in flexion and extension was 110-150° (mean, 135.9°) and 0-27° (mean, 12.9°), respectively. According to Jupiter et al. elbow score system, the results were excellent in 14 cases, good in 2 cases, and fair in 1 case; the excellent and good rate was 94.1%. One patient underwent recurrence at 1 month after removal of the Kirschner wire, and lateral closing wedge osteotomy was performed again after 1 year. Conclusion Lateral closing wedge osteotomy is a safe and effective surgical procedure in correcting traumatic cubitus varus deformity in children, which is easy to operate and can be effective in reducing the complications.