To analyze and compare the effectiveness of the closed reduction with elastic intramedullary nailing and open reduction with Kirschner wire fixations in the treatment of O'Brien type III radial neck fractures in children.Between November 2007 and November 2010, 31 children with O'Brien type III radial neck fractures were treated by the closed reduction with elastic intramedullary nailing fixation (closed reduction group, n=18) and by the open reduction with Kirschner wire fixation (open reduction group, n=13). There was no significant difference in age, gender, disease duration, and fracture classification between 2 groups (P > 0.05).The incisions of 2 groups healed primarily. All the patients were followed up 1-2 years (mean, 1.5 years). Limitation of the elbow extension occurred in 2 cases of the closed reduction group, limitations of the elbow extension, flexion, and forearm pronation in 6 cases of the open reduction group. There was no significant difference in elbow flexion, extension, pronation, and supination between affected side and normal side in the closed reduction group (P > 0.05). Except in supination (P > 0.05), there were significant differences in flexion, extension, and pronation between affected side and normal side in the open reduction group (P < 0.05). According to Metaizeau's grading criterion, excellent results were achieved in 16 cases and good in 2 cases in the closed reduction group; excellent results were achieved in 4 cases, good in 4 cases, fair in 3 cases, and poor in 2 case in the open reduction group; and there was significant difference between 2 groups (Z=3.435, P=0.001). The X-ray films showed anatomical reduction in 2 groups before removal of internal fixation; redisplacement occurred in 4 cases after removal of internal fixation in the open reduction group, no redisplacement occurred in the closed reduction group. There was no avascular necrosis of radial head and epiphyses during follow-up.Comparison with the open reduction with Kirschner wire fixation, the closed reduction with elastic intramedullary nailing fixation is a reliable and good treatment for O'Brien type III radial neck fractures in children, because it has the advantages of minimal invasion, easy operation, stable fixation, early mobilization, and less complication.