Background and purpose — The incidence of forearm shaft fractures in children has increased and operative treatment has increased compared with nonoperative treatment in recent years. We analyzed the long-term results of nonoperative treatment.Patients and methods — We performed a population-based age- and sex-matched case-control study in Vaasa Central Hospital, concerning fractures treated in the period 1995–1999. There were 47 nonoperatively treated both-bone forearm shaft fractures, and the patients all participated in the study. 1 healthy control per case was randomly selected and evaluated for comparison. We analyzed clinical and radiographic outcomes of all fractures at a mean of 11 (9–14) years after the trauma.Results — The main outcome, pronosupination of the forearm, was not decreased in the long term. Grip strength was also equally as good as in the controls. Wrist mobility was similar in flexion (85°) and extension (83°) compared to the contralateral side. The patients were satisfied with the outcome, and pain-free. Radiographally, 4 cases had radio-carpal joint degeneration and 4 had a local bone deformity.Interpretation — The long-term outcome of nonoperatively treated both-bone forearm shaft fractures in children was excellent.