Mild idiopathic adulthood ductopenia (IAD) is a rare cholestatic disease of unknown cause and characterized by interlobular bile duct loss in less than 50% of the portal tracts. We describe the case of a middLe-aged male who presented with persistent elevation of transaminases and alkaline phosphatase. He had a normal biliary tree on endoscopic retrograde cholangiopathy and negative anti-mitochondrial antibody. His liver biopsy specimen showed chronic biliary disease, duct loss in 4 out of 15 portal tracts and prominent cholestasis. Based on the work-up, he likely had mild IAD. Liver transplantation would be necessary if his disease becomes progressive.