To identify factors associated with and to describe treatment outcomes of pediatric subacute or chronic osteomyelitis (S/CO), we retrospectively identified 52 patients with S/CO from January 1994 to November 1999 seen at a large pediatric hospital infectious disease clinic. S/CO was defined by the following: >10 days of clinical symptoms; radiographic, surgical, or pathologic changes consistent with S/CO; or relapse of prior osteomyelitis. Of these patients 63% were male, median age 9 years. Bones involved included vertebra (19% of subjects), femur (17%), finger (12%), humerus (10%), and tibia (8%). Sixty-five percent had at least 1 risk factor (most commonly hardware, neurologic disease or preceding trauma, sepsis, or surgery). Blood, bone, or wound aspirate cultures were positive in 67%, most commonly for Staphylococcus aureus. Erythrocyte sedimentation rate (ESR) was elevated in 88% of 41 patients at the time of diagnosis. Intravenous antibiotics were given for a median of 6 weeks and oral antibiotics for a median of 4.5 months. One child had a complication. In conclusion, consideration of S/CO should be high when predisposing factors are present. ESR may be useful for determining effectiveness and duration of therapy. With prolonged antibiotic therapy nearly all patients demonstrated resolution of disease.