The infection of the bone marrow system caused by methicillin-resistant Staphylococcus aureus (MRSA) leads to a variety of common diseases which usually occur in children under the age of 12. Vancomycin (VCM) is the first-line therapy for MRSA-caused serious infections such as bacteremia, infective endocarditis, osteomyelitis, meningitis, pneumonia, and severe skin and soft-tissue infection (e.g. necrotizing fasciitis) with a recommended dosage of 15-20 μg/mL. In this study, we first report a case of a child with MRSA-caused osteomyelitis who was successfully cured by VCM at a concentration of 4.86 μg/mL. VCM's clinical daily dose of more than 4 g was of concern in light of recent evidence suggesting the increased risks of nephrotoxicity and red man syndrome when Cmin ⩾15 μg/mL and doses ⩾10 mg/kg in children. As far as we know, this is the first report on the lower dose of VCM in children with MRSA osteomyelitis.