The prevalence of impaired renal acidification in alcoholic liver disease and its relationship to clinical and biochemical features were evaluated during a one-year period in a 60-bed liver unit. No cases of overt renal tubular acidosis (RTA) were found; all of 12 patients with low serum bicarbonate values and normal anion gap proved to have chronic respiratory alkalosis. However, there was a 57% prevalence of incomplete distal RTA in 42 patients who were tested with an acid load. Subjects with RTA had higher serum bilirubin levels (5.3 +/- 6.1 v 2.1 +/- 2.7 mg/dL) and lower prothrombin times (45% +/- 22% v 64% +/- 20%). Urinary pH correlated directly with serum bilirubin levels (r = +.38) and inversely with prothrombin times (r = -.46). The frequency of ascites and encephalopathy did not differ notably between the two groups of patients. No pathogenetic relation was observed with avid sodium retention, decreased excretion of nonreabsorbable anions, and elevated urinary excretion of bile acids. Therefore, we conclude that impaired renal acidification in alcoholic liver disease may be a sign of liver cell failure since it is more frequently observed in patients with a greater degree of liver dysfunction.