Laparoscopic findings of the liver in 13 cases with primary biliary cirrhosis (PBC) diagnosed by wedge or needle biopsy were investigated. The characteristic features of laparoscopic appearance—gentle undulation—were observed in 11 out of 13 (85%) patients with PBC. These gentle undulations were irregularly shaped areas from 0.5 to 3 cm in diameter. Those observed in s-PBC were greater in number and more pronounced than those in a-PBC. In the concave areas of these undulations, the number of portal tracts was significantly greater than in the convex areas (p < 0.005). On the contrary, the number of interlobular bile ducts in the concave area was significantly less than in the convex area (p < 0.005). Therefore, gentle undulation was relatively specific to PBC, and was caused by scar formation and chronic non-suppurative destructive cholangitis in the portal area.