It is well known that early diagnosis and early treatment is very important for the patient with congenital dislocation of the hip joint to provide a favorable function in the whole life. The goal of treatment, which is either conservative or operative, is to replace the dislocated hip into the socketand restore its anatomical position. If the head is reduced lately, it may subluxate or redislocate. As a result, secondary osteoarthritis will be complicated in such hips at a laterdate The most cases of congenital dislocation of hip have a increased anteversion and vaglus deformity. It is known that these deformity are cause of redislocation or subluxation, and should be corrected by varus or derotational varus osteotomy to restore for normal cephalocotyloid relationship. We analized 18 residual subluxation of hips which had been treated by derotational varus osteotomy. The results obtained are as follows. 1. Regardless of the age at the time of osteotomy and the amount of varization, the neck-shaft angle corrected to nearly normal in all cases within 3 years after the osteotomy. 2. Acetabular development, indicated by acetabular index, was satisfactory when the osteotomy was done before 4 years, but unsatisfactory in the cases after 4 years of age. 3. Coxa valga epiphysialis of the subluxated head corrected spontaenously after osteotomy in all cases. 4. Subluxated head, indicated by C-E angle and migration percentage, reduced in the cases who had by the derotational varus osteotomy in patients below age of 4 years, but it persisted without further luxation in the cases over 4 years of age.