Non-A, non-B viral hepatitis may cause many different hematologic abnormalities, such as transient anemia, granulocytopenia, thrombocytopenia, atypical lymphcytosis, or aplastic anemia. We describe a patient who developed a myelodysplastic syndrome (refractory anemia with excess blasts) after prednisone therapy for non-A, non-B chronic active hepatitis. We discuss the effects of non-A, non-B viral infection on the bone marrow and potential explanations for the previously unreported association with myelodysplastic syndrome.