Background/aims: This study describes six female patients with elevated alkaline phosphatase, gammaglutamyltranspeptidase and serum autoantibody levels and histological features of bile duct damage overlapping those of autoimmune hepatitis. Methods: Four patients had chronic hepatitis and two had clinical cirrhosis. Serological markers of hepatitis B and C, cytomegalovirus, Epstein Barr virus and herpes simplex virus were negative. In all six patients, serum anti mitochondrial antibody and serum M2 antibodies were absent, a feature which continued during and subsequent to the study period. Four patients had positive serum antinuclear antibody of homogeneous type and three had positive serum smooth muscle antibody but lower titers than cases reported in the literature. Liver-kidney microsomal antibody and serum perinuclear antineutrophilic cytoplasmic antibody were negative in all subjects. Two subjects had human leucocyte antigen DR4 and one had DR3. Endoscopic retrograde cholangiopancreatography was performed on five patients and was found to be normal. Histological features of four specimens showed moderate portal inflammation, moderate to severe lobular infiltration, limiting plate destruction, fibrosis and ductal destruction prior to therapy. One of the cirrhotic patients had micronodular cirrhosis. Results: Four patients treated with either prednisolone or prednisolone with azathioprine showed biochemical and clinical improvement. Follow-up biopsies revealed decreased hepatic inflammation and in particular, improvement in lobular inflammation, but bile duct destruction persisted following therapy. Conclusions: Autoimmune cholangitis may be an immune-mediated disorder showing a substantial response to immunosuppressives. While the paranchymal damage can be suppressed, biliary features of the disease seem not to respond therapy.