Thyroid dysfunction has heen reported as a side effect of alpha-interferon(IFN) therapy. The incidence of thyroid disorders was 1.2 - 12%' duripg 1FN therapy for chronic active hepatitis. We experienced a case of hypothyroidism developed after IFN therapy in a 48 year-old man with chronic hepatitis B. Baseline thyroid function before IFN therapy was normal and thyroid auioantibodies were also negative. High tiers ol' antimicrosomal antibody and anti-thyroglobulin antibody appeared and severe hypothyroidism followed at 6 months after starting the IFN therapy.
