The purpose of this study is to clarify the limit of extended hepatectomy, such as 84% hepatectomy for normal liver and 70% hepatectomy for Dimethylnitrosamine-induced cirrhotic liver in dogs, using ligation of the portal vein branch (PBL) in advance. Portal vein branch could be ligated up to 84% area in normal liver and 70% area in cirrhotic liver, for survival. Four weeks after PBL the non-ligated area of the liver was obviously enlarged, and the hepatic function was almost equal to that before PBL. Four weeks after PBL of 84% area in normal liver and 70% area in cirrhotic liver, the ligated area was resected by two staged procedure. Although the four-week survival rates after one staged 84% hepatectomy in normal liver and 70% hepatectomy in cirrhotic liver were 22.2% and 0% respectively, they markedly improved such as 66.7% and 50.0% after two staged hepatectomy respectively, and they were 42.1% and 30.0% respectively even if the death of PBL was count in. ICG Rmax prior to hepatectomy after PBL indicated clearly the functional resectability of the liver. The remnant liver function after two staged hepatectomy was significantly better than that after one staged hepatectomy, due to sufficient hepatic blood flow.