Abstract Subcutaneous injection of hyperoncotic polyethylene glycol (PG) solution produces hypovolemia in rats, while total infrahepatic ligation of the inferior vena cava (IVC) presumably increases renin secretion and circulating levels of angiotensin. The previous report indicated that rats receiving either (or both) of these treatments and given only 0.15 m NaCl to drink would consume large amounts of this fluid. Nevertheless, in the present experiments most rats initially preferred water and drank little saline when both fluids were available. It appears that the accumulation of ingested water in these oliguric animals inhibited thirst and thereby interfered with saline intakes. PG-treated rats later developed a sodium appetite and, by consuming increased amounts of saline, always repaired their plasma deficits. In contrast, IVC ligated rats did not evidence sodium appetite during the 24 hr test period, even following PG injection treatments. These results suggest that the renin-angiotensin system may not have an important role in stimulating sodium appetite in rats, and that some aspect of the combined IVC ligation and PG injection treatment, probably associated with extreme oliguria, may inhibit this drive.