Cardiac output, plasma volume and renal plasma flow were determined to evaluate hemodynamic changes in 29 patients with cirrhosis of the liver. The results obtained were as follows. 1) The mean plasma volume was 3793¡¾895ml and it was significantly higher than the normal controls. The mean blood volume (5266¡¾1222ml) and blood volume per kg body weight (95.7¡¾23.41ml) were also increased significantly. The mean plasma volume per kg body weight (69.1¡¾19.1ml) showed increased tendency and the mean difference between blood volume and plasma volume per kg body weight (26.4¡¾7.05ml) was in lower limit of normal range. 2) The mean cardiac output was 7708¡¾2652ml/min and it was significantly increased. The mean cardiac index (4924¡¾1998ml/min/M2), stroke volume (96.2¡¾34.2ml/beat), stroke index (62.3¡¾27.34ml/beat/M2) and fractional cardiac index (1.54¡¾0.577) were also increased significantly. The mean total peripheral resistance was 1664¡¾753.8 dynes sec cm-5 M2 and it was significantly lower than the normal controls. 3) The mean renal plasma flow was 537¡¾146.8ml/min/1.73M2 and it was normal to decreased tendency. The mean endogenous creatinine clearance (66.7¡¾23.0ml/min/1.73M2) was significantly decreased. Filtration fraction was variable, but it was slightly lower than normal in most cases. The mean renal fraction of cardiac output (11.4¡¾6.27%) was relatively decreased. 4) Although renal plasma flow was normal or decreased in general, it was definitely diminished in patients with creatinine clearance less than 60ml/min/1.73M2, resistant ascites, and signs of azotemia (elevated BUN and serum creatinine). 5) Diminished glomrular filtration rate with low filtration fraction and decreased renal fraction of cardiac output observed strongly supported increased renal afferent arteriolar resistance. 6) Renal circulatory impairment preceded azotemia or oroliguria in cirrhosis. 7) Clinical findings and liver function were not correlated with hemodynamic changes, except for esophageal varices associated with high cardiac output observed. 8) No definite correlation of renal hemodynamics with plasma volume or cardiac output was found.