We performed percutaneous liver biopsy in nine children who had received a weekly dose of methotrexate, 10 mg/m2 per week, for at least 3 years to address the concern about subclinical liver toxicity from single, weekly, low-dose methotrexate therapy for juvenile rheumatoid arthritis. No patient had clinical or biochemical evidence of liver injury. All biopsy results were interpreted as normal. These results suggest that the recommendations of the American College of Rheumatology for adults receiving single weekly methotrexate therapy for rheumatoid arthritis can be extended to children.