We retrospectively reviewed our results of treatment of two groups of children with developmental dysplasia of the hip (DDH) aged between 13 and 17 months. The nonoperative group consisted of 16 patients (17 hips) who were treated by closed reduction and casting with or without skin traction. There were four hips with mild degrees of avascular necrosis, and one hip with a failed reduction. Before further treatment, there were one hip in Severin class I, nine in class III, six in class IV, and one in class VI. Subsequent open reduction or pelvic osteotomy was required in those hips with failed reduction and residual dysplasia. The operative group consisted of 32 patients (32 hips). Open reduction and Salter osteotomy were performed without preoperative traction. There was one hip with redislocation due to improper use of a short spica and two hips with a mild degree of avascular necrosis. In > 2 years and 3 months of follow-up, 13 hips were in Severin class I, 18 in class II, and one in class III. The treatment time was significantly shortened in the operative group. We conclude that neglected DDH in patients of walking age can be safely and effectively treated by open reduction plus Salter osteotomy.