In liver surgery, postoperative bile leakage occurs with a steady incidence and hampers the clinical course of patients, even giving rise to mortality. Clinical parameters of 20 patients complicated with postoperative bile leakage were retrospectively compared with those of 394 patients without this complication after liver resection. On multivariate analysis, significant independent risks for postoperative bile leakage included the following: (1) high-risk operative procedure that exposes the major Glisson's sheath on the cut surface, including caudate lobectomy, central bisegmentectomy, and right anterior sectionectomy, (2) repeated hepatectomy, and (3) the presence of intraoperative bile leakage. The subgroup of patients in whom (1) leakage occurred from an injured bile duct with stenosis, or (2) leakage occurred from the divided bile duct suffered for a prolonged period. Patients at high risk require more vigilant observation and expeditious treatment perioperatively. During this process, adequate classification of the type of biliary injury would be helpful to the clinician in determining optimal strategies.