The surgical management of patients with neglected developmental dysplasia of the hip (DDH) after the age of 6 years has been the subject of controversy. We present 11 cases (16 hips) of neglected DDH that were treated operatively by means of open reduction and derotational subtrochanteric osteotomy. Patient age ranged between 10 and 17 years (mean, 12 years). Follow-up ranged from 5 to 13 years (mean, 8.7 years). The results have been satisfactory both clinically (evaluated using the modified Harris hip score) and radiographically (evaluated using Severin's classification). Our data suggest that neglected DDH cases, not only during early childhood, but also in the periadolescent period, should be considered for surgical treatment.