BACKGROUND: Clinical outcomes of children with bacterial septic arthritis, common in the pediatric age group, are often satisfactory with early recognition, prompt surgical drainage, and appropriate antibiotic therapy. However, the optimal duration and route of antibiotic administration for treatment of septic arthritis continues to be debated, as traditional treatment favored longer intravenous (IV) therapies yet oral regimens are increasingly available that are more cost effective, safe and produce satisfactory disease resolution. METHODS: Records of 186 patients from two children's hospitals, one that was thought to convert from IV to oral antibiotic therapy considerably earlier than the other, treated between 1985 and 1995 for bacterial septic arthritis were reviewed. Patients with concurrent osteomyelitis were excluded. RESULTS: Patients at Hospital #1 were converted to oral antibiotics after 7.4±7.4 days of IV antibiotic therapy and at Hospital #2 after 18.6±13.6 (P<0.001) days of IV therapy. Both groups received an average of four weeks of total antibiotic treatment. There was similar time to defervescence (2.4±3.2 d vs. 2.4±3.8 d, P>0.05) and to normalization of erythrocyte sedimentation rate (35.7±19.7 d vs. 33.8±44.9 d, P>0.05) in the patients converted to oral therapy early compared to those converted late. One case of mild avascular necrosis with no clinical disability developed in a patient from Hospital #2. CONCLUSIONS: We conclude that the clinical outcome in patients with septic arthritis converted to oral antibiotic therapy early in their treatment based on defined criteria was similar to those converted late.