Unstable fractures of the forearm in children present problems in management and in the indications for operative treatment. In children, unlike adults, the fractures nearly always unite, and up to 10° of angulation is usually considered to be acceptable. If surgical intervention is required the usual practice in the UK is to plate both bones as in an adult. We studied, retrospectively, 32 unstable fractures of the forearm in children treated by compression plating. Group A (20 children) had conventional plating of both forearm bones and group B (12 children) had plating of the ulna only. The mean age was 11 years in both groups and 23 (71%) of the fractures were in the midshaft. In group B an acceptable position of the radius was regarded as less than 10° of angulation in both anteroposterior (AP) and lateral planes, and with the bone ends hitched. This was achieved by closed means in all except two cases, which were therefore included in group A. Union was achieved in all patients, the mean time being 9.8 weeks in group A and 11.5 weeks in B. After a mean interval of at least 12 months, 14 children in group A and nine in group B had their fixation devices removed. We analysed the results after the initial operation in all 32 children. The 23 who had the plate removed were assessed at final review. The results were graded on the ability to undertake physical activities and an objective assessment of loss of rotation of the forearm. In group A, complications were noted in eight patients (40%) after fixation and in six (42%) in relation to removal of the radial plate. No complications occurred in group B. The final range of movement and radiological appearance were compared in the two groups. There was a greater loss of pronation than supination in both. There was, however, no limitation of function in any patient and no difference in the degree of rotational loss between the two groups. The mean radiological angulation in both was less than 10° in both AP and lateral views, which was consistent with satisfactory function. The final outcome for 23 patients was excellent or good in 12 of 14 (90%) in group A, despite the complications, and in eight of nine in group B (90%). If reduction and fixation of the fracture of the ulna alone restores acceptable alignment of the radius in unstable fractures of the forearm, operation on the radius can be avoided