The purpose of this study was to compare the results of operative versus nonoperative treatment for posttraumatic genu valgum. It is a retrospective chart and radiograph review of all patients with the diagnosis of posttraumatic genu valgum from our institution and from data obtained in response to 389 letters sent to the members of the Pediatric Orthopaedic Society of North America (POSNA). The complementary physeal shaft (CPS) angle and the tibial femoral angle (TFA) were measured at the time of injury, at maximal deformity, and at latest follow-up. Fifteen patients were identified, 10 in the nonoperative group and five in the operative group. In both groups, the valgus deformity progressed over a 20-month span. In both groups, the valgus deformity improved at the time of follow-up. There was no significant difference in the CPS angle or TFA, between groups at the time of injury, at maximal deformity, or at follow-up.