We describe a case of an 11-year-old girl who presented with osteomyelitis of the vertebrae and right femur due to Bartonella henselae. Her only symptom was prolonged fever without focal pain. Magnetic resonance imaging (MRI) and nested polymerase chain reaction (PCR) were useful for the diagnosis. Osteomyelitis due to B. henselae should be considered in cases of prolonged fever of unknown origin.