In six patients avascular necrosis of the normal hip developed while the opposite hip was being treated for dislocation. The ages of the patients ranged from one to sixteen months. All children were immobilized bilaterally with plaster casts. In addition to avascular necrosis of the originally normal hips, the dislocated hips also became avascular. The problem in five of the originally normal hips resolved without serious final deformity, but in one the growth plate and the capital epiphysis closed prematurely, resulting in a short femoral neck.