Congenital coxa vara is a distinct entity to be separated from other forms of coxa vara, such as acquired one. In spite of its relative infrequency, its natural history and results of treatment have been well defined as a hip disorder of childhood. The behavior of the developmental variety is unlike that of other forms because of the nature of its osteocartilagenous femoral neck defect. We report a boy who have had subtrochanteric valgus osteotomy for the condition at age of 8 years. The growth of the proximal femur including neck-shaft angle, capital physis and greater trochanter after valgus osteotomy was observed. The neck-shaft angle of preoperation was 100°, immediate postoperation 145°and final 125°. The articulo-trochanteric distance index of preoperation was 0.14, immediate postoperation 0.75 and final 0.20. No further changes of the neck-shaft angle occured after capital physeal closure. While articulo-trochanteric distance continued to decrease until closure of trochanteric physis. Our conclusion is that a premature closure of capital physis should be expected and that early trochanteric advancement surgery has to be done for the prevention of Apontaneous revarization and decrease of articulo-trochanteric distance(ATD).