A type of chronic hepatitis designated as chronic septal hepatitis was distinguished morphologically from chronic aggressive and chronic persistent hepatitis: 18 cases were separated from chronic aggressive hepatitis by the absence of destruction and inflammatory infiltration of the limiting plate and from chronic persistent hepatitis by the presence of connective tissue septa. Clinically, many patients were asymptomatic despite hepatomegaly and elevated serum transaminase activities while immune markers were usually absent from the serum. Chronic septal hepatitis was often seen after corticosteroid therapy of chronic aggressive hepatitis, but it also occurred de novo. Transition to cirrhosis was not observed during follow-up for 5 years to 2 months except in one case with high serum gamma-globulin. Until a classification based on etiology becomes available chronic septal hepatitis might be separated from other types of chronic hepatitis.