The purpose of this study was to compare short-term radiographic and clinical results of pediatric both-bone diaphyseal forearm fractures treated with intramedullary nail fixation using titanium nails or K-wires. This was a prospective comparative trial. In total, 43 patients with both-bone open or closed forearm fractures who underwent surgical treatment with intramedullary fixation were randomly classified into two groups. Three patients did not return for the follow-up and were excluded from the study. Twenty of the 40 patients were assigned to the elastic stable intramedullary nail group and 20 were assigned to the K-wire group. Demographic data suggested no difference between the two groups except for the side of injury. Perioperative data and radiological and clinical outcomes were evaluated. The cohort comprised 5 girls and 35 boys whose mean age was 11.60 ± 2.69 years. Except the proportion of patients who were conservatively followed up preoperatively, all perioperative data were similar between the groups. Radiographic and functional results were similar. There were two delayed unions; one pin track infection and one re-fracture. Intramedullary fixation of forearm fractures in children with titanium nail or K-wire does not affect radiological and clinical results. Both elastic stable intramedullary nail and K-wire fixation were effective in stabilizing pediatric diaphyseal forearm fractures.