To evaluate the results of a thoracoabdominal hepatectomy and a transdiaphragmatic hepatectomy for hepatocellular carcinoma in patients with impaired liver function.Retrospective study.A university hospital in Japan.Twenty-seven patients who from 1991 to 1996 underwent a thoracoabdominal hepatectomy for hepatocellular carcinoma located mainly in the superior portion of the liver and 20 patients who underwent a transdiaphragmatic hepatectomy for hepatocellular carcinoma located near the diaphragm.Morbidity, survival, and disease-free survival after each operation. Comparisons were then made with 183 patients who had undergone an ordinary transabdominal hepatectomy during the same period.In the thoracoabdominal hepatectomy group, 17 patients underwent a partial resection, 4 patients underwent a subsegmentectomy, and another 6 patients underwent either a segmentectomy or a procedure that was greater in size than a segmentectomy, whereas all of the patients in the transdiaphragmatic group underwent a partial resection. The morbidities in the thoracoabdominal group included pleural effusion in 6 patients (22%); intra-abdominal infection in 5 patients (19%); and hepatic failure in 3 patients (11%), of whom 1 died (mortality rate, 4%). In the transdiaphragmatic group, only 2 patients (10%) had non-life-threatening complications. The cumulative survival rates and the disease-free survival rates of the patients at 3 years were 51% and 24% in the thoracoabdominal hepatectomy group and 62% and 30% in the transdiaphragmatic hepatectomy group; no significant differences were observed when these findings were compared with those of patients who had undergone a transabdominal hepatectomy.The outcomes of the patients undergoing thoracoabdominal hepatectomy and those undergoing a transdiaphragmatic hepatectomy were generally satisfactory in spite of the fact that these procedures were performed on patients with cirrhosis and impaired liver function.