Background: The prevalence of neglected developmental dysplasia of the hip (DDH) has been decreasing. Nowadays, the disease is rarely seen in walking age children. The purpose of this study is to assess the results of simultaneous osteotomy of femur and pelvic bones in such children.Method: We performed a retrospective study on 30 children aged 3.8±0.9 (range: 1.5-7) years old, with DDH who underwent surgical operation in our hospital from August 2001 to September 2006. Tönnis and Severin grading systems were used to classify the radiographic status of the hip in pre- and postoperative era, respectively. Improvement in function and limp was also evaluated by the modified McKay’s classification.Results: From the 30 cases, six patients excluded in the course of the study and among the remaining patients, 12 had bilateral involvement. The mean follow-up period was 7.6±0.8 (range: 5.1-11.3) years. During the last visit, radiographic status of the operated joints, according to Severin classification was as follows: Class I: 12 patients; Class II: 20 patients; Class III: 3 patients; Class IV: 1 patient; and Class VI: 1 patient. Conclusion: Although through the follow-up, two hips subluxated, necrosis happened in three and one joint was re-dislocated, simultaneous femoral and innominate osteotomy in the walking age children with DDH has relatively good clinical outcomes.