1. The intrarenal distribution of plasma flow was determined with a technique based on the analysis of the transit time of sodium o-[131I]- iodohippurate through the kidney in 43 patients with cirrhosis with near-normal total renal perfusion. 2. Twenty-five of the patients had an abnormal pattern of transit times, suggesting a redistribution of plasma flow from outer cortical to juxtamedullary nephrons. 3. Plasma renin activity ranged from below normal to six times normal and high values were found only in patients showing an abnormal pattern of transit times. The latter was also found to be related to sodium retention and a reduced renal capacity to excrete free water.