Purpose The goal of this study was to compare results of open arthrotomy versus arthroscopic drainage in treating septic arthritis of the hip in children. Methods This prospective controlled study was conducted on twenty patients (20 hips) with acute septic arthritis of the hip. Diagnosis was suspected if there was: a history of fever, non-weight-bearing on the affected limb, erythrocyte sedimentation rate (ESR) of at least 40 mm/h, and white blood cell count of more than 12,000 cells per cubic millimeter. Diagnosis was established by ultrasonographic examination of the affected hip followed by ultrasound-guided aspiration of the joint. Patients were allocated to have either open arthrotomy or arthroscopic drainage of the joint. There were ten patients (ten hips) in each treatment group. The mean age of the patients was 7.3 years in the arthrotomy group, and 8 years in the arthroscopy group. The mean temperatures for the arthrotomy and arthroscopy groups were 38.8 and 38.7°C, respectively. All the children were unable to bear weight on the affected limb.Results Staphylococcus aureus was the most common causative microorganism in both groups. The mean duration of the children's hospital stay was 6.4 days in the arthrotomy group and 3.8 days in the arthroscopy group. The difference was highly significant. Infection could be eradicated in all patients of both groups. At the latest follow-up, seven children in the arthrotomy group (70%) had excellent results and three children (30%) had good results. In the arthroscopy group, nine children (90%) had excellent results and one child (10%) had good results. The difference was not statistically significant. Conclusions Arthroscopic drainage is an effective method in treating septic arthritis of the hip. It is a minimal invasive procedure which is associated with less hospital stay. Arthroscopic drainage of septic arthritis of the hip in children is a valid alternative procedure in early uncomplicated cases and for orthopedic surgeons skilled in pediatric arthroscopy.