The activity of glomerulopressin, a putative renal vasoregulatory hormone that is synthesized in the liver, was assayed in male rats with carbon tetrachloride-induced cirrhosis and the results were compared to glomerulopressin activity in normal-control and pair-fed animals. Glomerulopressin activity in blood samples collected from the hepatic vein of the cirrhotic group was significantly lower than the activity in the normal-control and pair-fed groups. Glomerulopressin activity in the normal-control and the pair-fed groups were not significantly different. The data support the concept that glomerulopressin deficiency in liver disease, such as cirrhosis, may play a role in the genesis of the functional renal failure associated with liver disease.