We retrospectively reviewed postoperative complications in 105 patients with hilar cholangiocarcinoma who underwent hepatectomy at Nagoya University Hospital from January 1990 through March 1999. Of the 105 subjects, 97 (92.4%) underwent resection of two or more Healey's segments of the liver. Combined portal vein resection was performed in 33 (31.4%) patients and pancreatoduodenectomy in 10 (9.5%). Twenty (19.0%) patients had no postoperative complications, another 39 (37.1%) patients had minor complication(s) only, and the remaining 46 (43.8%) developed major complication(s). The morbidity rate reached as high as 81.0%. Major complications required relaparotomy in 11 (10.5%) patients. Of the 46 patients with major complication(s) 36 recovered; the remaining 10 patients died of liver failure with other organ failure(s) or of intraabdominal bleeding 12, 14, 18, 21, 57, 75, 75, 87, 93, or 134 days after surgery. Thus the 30-day mortality was 3.8% and the overall mortality 9.5%. Pleural effusion was the most frequent complication found in 66 (62.9%) patients, followed by wound sepsis in 39 (37.1%), and then liver failure in 29 (27.6%). Liver failure developed in 16.7% of 48 patients with less than 50% liver resection and in 36.8% of 57 patients with 50% or more resection (P < 0.05). Other organ failures, including renal, respiratory, gastrointestinal, and hematologic failures, developed as a sign of multiple organ failure following liver failure in most patients or preceding liver failure in a few patients. None of the six patients with four or more organ failures survived. Hepatectomy for hilar cholangiocarcinoma is risky owing to impaired hepatic functional reserve in jaundiced patients and the technical difficulty associated with hepatobiliary resection. Our goal is to reduce mortality to less than 5% while keeping a high resectability rate (above 80%).