The clinical and pathological findings of idiopathic ductopenia were studied in a 30-year-old woman who initially manifested jaundice and pruritus. Serum biochemical tests of liver function indicated severe and progressive cholestasis. Viral hepatitis markers and circulating autoantibodies were absent. The patient had a normal cholangiogram and lacked evidence of inflammatory bowel disease. Histological examination of a liver specimen showed severe cholestasis and absence of interlobular bile ducts. Severe jaundice and intractable pruritus developed in the patient and served as the indications for liver transplantation 4 months after initial examination. Transplantation resulted in prompt and complete resolution of the jaundice and pruritus. Two types of idiopathic adulthood ductopenia associated with different prognoses are recognized. Patients with type 1 idiopathic adulthood ductopenia are asymptomatic or manifest symptoms of cholestatic liver disease. They tend to have less destruction of the intrahepatic bile ducts on liver biopsy specimens. Their clinical course ranges from spontaneous improvement to progression to biliary cirrhosis. In contrast, patients with type 2 idiopathic adulthood ductopenia generally manifest initial symptoms of decompensated biliary cirrhosis, have extensive destruction of the intrahepatic bile ducts on liver biopsy, and frequently require orthotopic liver transplantation.