The authors analyze the results of Chiari pelvic osteotomy in treatment of sequellae of hip osteochondritis with 11 cases of children 6 to 10 years old, operated and reviewed with an average follow up of 21 months. They used the operative procedure decided by Chiari, on orthopaedic table, followed by plaster cast immobilisation for 3 weeks. The Xray results are specially analyzed as the peroperative functional troubles were absent. This procedure is mainly effective on articular congruence with gain not only in lateral but also in anterior head-coverage. The secondary modelling appears to affect either the head and the acetabulum. But the medialization remains poor, which is explained by an analyze of the lower fragment operative displacement. Actually, this operative procedure may be used in late osteochondritis with a coxa magna and specially when a coxa vara or a short neck contra-indicate a femoral osteotomy.