Septic arthritis of the hip has been treated traditionally by surgical drainage. Recent reports have described repeated aspirations as an adequate and safe treatment. The aim of the present study was to assess the success of treatment of septic arthritis of the hip by repeated aspirations and to identify predictive factors for failure. Medical records were retrospectively reviewed for all patients treated by ultrasound-guided aspiration and intravenous antibiotics between 2002 and 2010. The demographic, clinical, laboratory, and outcome data were recorded. Findings were compared between patients who responded to this treatment and those who subsequently required surgery. A total of 42 patients fulfilled the inclusion criteria. Of the total 33 responded to repeated aspirations and nine required surgical drainage. The mean age of patients requiring surgery was 8.3 years compared with 2.6 years for those responding to aspirations. Age older than 10 years was associated with a 57% rate of failed conservative treatment compared with 14% for age younger than 10 years. There was no significant difference between the groups in any of the other parameters measured. Follow-up of the operated group after an average of 7.44 years showed no unfavorable results. In children with septic arthritis of the hip, hip decompression may be achieved with repeated aspirations and lavage combined with antibiotics, sparing patients the risks of anesthesia and surgery. Age older than 10 years at admission may serve as the cutoff for initial conservative treatment. The postponement of surgery did not cause any long-term morbidity. Level of evidence: Level III; patients compared on the basis of outcome of conservative treatment of septic hip arthritis.