Auto-antibodies are described frequently in adults with chronic HCV, with thyroid antibodies present in14% and autoimmune hepatitis antibodies in up to 90%. These antibodies have prevented some adults from undergoing or successfully completing treatment with interferon. Although children with HCV generally tolerate treatment better than adults and have a higher response rate, little is known about the frequency with which autoantibodies are present. Understanding this baseline feature may be important in developing recommendations for treatment of pediatric patients with chronic HCV.