The mortality rate of 67 sequential cases of acute renal failure (ARF) accompanied byjaundice was compared with the mortality rate of 168 patients without jaundice. The mortality rate in the group of jaundiced patients was 57%, significantly greater (p < 0.05) than the 42% mortality in patients without jaundice. The mortality rate correlated with serum bilirubin levels; patients with serum bilirubin greater than 20 mg% had a mortality rate of 85%, whereas patients with levels lower than 10 mg% had a mortality rate of only 33%. Average blood pressures were significantly lower (p < 0.01) in patients with jaundice than in those without. The data indicate that: (1) ARF accompanied byjaundice carries a worse prognosis; (2) reduced blood pressure which accompanies this condition may be an aggravating factor, and (3) serum bilirubin levels may be used as a prognostic index.