This study reports on the late results of septic arthritis of the hip in 29 children, after an average follow-up of 12 years 7 months. The purpose of the study is to show the severe destruction caused by infection in children's hips and to reemphasize the necessity for early diagnosis and treatment. The 29 patients were divided into two groups according to age (0-4 weeks and 1 month-3 years of age) because of the different prognoses. Functional and anatomical evaluations of the hips were performed. In some cases there was no correlation between the functional results and the anatomical situation of the joint. Our results showed that the prognosis is worse in young children and also in cases with associated osteomyelitis of the proximal femur. Eleven of the 16 neonates were premature. Late reconstructive surgery is difficult and does not always give the desired functional and anatomical improvement. The most important factor influencing the end result, however, is the time between beginning of symptoms and treatment; that is the only factor, also, we can change to improve the ultimate outcome of the disease.