Portal vein obstruction due to a thrombus may be encountered in liver cirrhosis. However, the effect of portal vein obstruction on hepatic hemodynamics and functions, and on collateral formation has not been clear in liver cirrhosis. To rectify this, the cirrhotic rat model with portal vein ligation was evaluated. In addition to the early recovery of hepatic blood flow, the reduction in hepatic blood flow after portal vein ligation was less in the cirrhotic rat than in the normal rat. The portogram showed that, in addition to hepato-fugal collaterals, hepato-petal collaterals developed well and early in the cirrhotic rat as compared with the normal rat. Although mitochondrial functions before portal vein ligation deteriorated in the cirrhotic rat, the decrease after portal vein ligation was less, and the recovery of function was earlier in the cirrhotic than the normal rat. The influence of portal vein obstruction on hepatic hemodynamics and functions in the cirrhotic rat was less than in the normal rat, due to earlier and significant formation of hepato-petal collaterals.