The purpose of this study was to evaluate and compare the outcome of single- and double-elastic stable intramedullary nailing (ESIN) for the treatment of pediatric both-bone forearm fractures. We retrospectively analyzed 49 children with both-bone forearm fractures treated with ESIN. Twenty-four patients were treated with single-ESIN (S-ESIN) to fixate the radius only, and the other 25 patients were treated with double-ESIN (D-ESIN) to fixate the radius and ulna. The duration of surgery, times of fluoroscopy, cost of hospitalization, period of castoff, union time, radiographic outcomes, clinical results, and postoperative complications were compared. The duration of surgery, times of fluoroscopy, and cost of hospitalization were significantly lower in the S-ESIN group; however, the average period of castoff was longer in the S-ESIN group. The incidence of delayed union of the ulna was significantly higher in the D-ESIN than in the S-ESIN group. Although the mean angulation deformity of the ulna in the S-ESIN group was significantly larger than in the D-ESIN group, both of them were acceptable (<10 degrees). Despite this, there was no difference in the loss of forearm motion and complication rates between the 2 groups. In conclusion, our data suggest that S-ESIN to fixate the radius alone remains an equally effective fixation method in the pediatric population compared with both-bone fixation and is our treatment of choice.