Thirty-eight children (39 hips) with septic arthritis have been reviewed in an effort to determine the factors most important to prognosis of the hip joint. The younger patients, 3 or more years later, had poorer results by roentgenographic classification. This was particularly true of patients under one year of age. Longer duration of disease from clinical onset to initiation of therapy also resulted in a poorer result. The outcome could not be clearly correlated with the causative organism or with open as opposed to closed treatment although the policy of management was strongly biased to open drainage. Sixty per cent of the infections were caused by Staphylococcus aureaus and the majority of the other cases by Streptococcus pyogenes and Hemophilus influenzae. The nonstaphylococcal organisms may be less destructive to the femoral head in infants.