Tubular handling of sodium and phosphate were studied in 4 patients with cirrhosis and ascites. The control group consisted of 5 patients with cirrhosis without sodium retention. The degree of phosphaturia was assumed to reflect proximal tubular reabsorption. Whereas fractional excretion of phosphate was comparable in both groups, fractional excretion of sodium was strikingly diminished in the patients with ascites. This observation suggests that sodium retention in these patients occurs beyond the proximal tubule. This interpretation is in accord with our previous observation, based on clearance data, that the proximal tubular reabsorption of sodium in cirrhosis may be normal even in the face of edema formation.