Abstract In contrast to chronic or subacute thyroiditis, Graves' disease rarely complicates IFN-α therapy for chronic viral C hepatitis. We report the case of a 51-year-old man in whom IFN-α treatment was followed by recurrence of Graves' disease 10 years after thyroidectomy was performed and the patient was declared cured. Despite severe thyrotoxicosis, combined IFN-α and ribavirin therapy was continued and radioiodine treatment was considered for Graves' disease