The intracellular potassium content of leukocytes, the extracellular fluid volume (82Br space), and exchangeable potassium were determined in 28 patients with cirrhosis of the liver (18 with ascites) and in 15 hospitalized controls. No intracellular potassium depletion could be identified in these patients. Leukocyte potassium was similar in cirrhotic patients with and without ascites (355.9 +/- 25.3 and 348.1 +/- 31.9 mEq/kg of dry solids, respectively) and in hospitalized controls (359.7 +/- 27.4) (mean +/- SD). The extracellular fluid volume was similar in controls and cirrhotics without ascites, but markedly increased in cirrhotics with ascites. The exchangeable potassium (mEq/kg of body weight) was similar in nonascitic cirrhotics and in hospitalized controls, but significantly lower in patients with cirrhosis and ascites. However, when the estimated weight of the extracellular fluid volume was substrated from the total body weight, thus obviating the influence of the increased extracellular fluid volume of ascitic patients in the body weight, the exchangeable potassium (mEq/kg of "corrected" body weight) was similar in cirrhosis with ascites (52.9 +/- 6.7 mEq/kg), nonascitic cirrhotics (55.8 +/- 6.1 mEq/kg) and hospitalized controls (55.0 +/- 8.3 mEq/kg), and a significant correlation was obtained between the exchangeable potassium and the leukocyte potassium content. In five patients, the measurements were repeated after relieving ascites with diuretics. No change was observed in the leukocyte potassium, but exchangeable potassium (mEq/kg of body weight) increased, reaching values not significantly different from controls or nonascitic cirrhotics. The exchangeable potassium (mEq/kg of "correct" body weight) did not change. Our results strongly suggest that potassium depletion was not present in the series of cirrhotic patients studied.