Specific electrical conductance (SEC) of the hepatic bile in 94 patients with cholelithiasis and concomitant pancreatitis was increased (p < 0.001) and depended on the degree of cholestasis and the morpho-functional state of the liver. The value of SEC of the intraoperative bile higher than 193 S/m is taken for a criterion of the diagnostics of biliary pancreatitis. The electrical conductance of urine during the first 4 days of observation decreased in patients with acute pancreatitis (p < 0.05), impaired carbohydrate metabolism and concomitant renal dysfunction. The value of SEC of urine lower than 238 S/m corresponds to acute pancreatitis. The investigation of physico-chemical indices of biological liquids in patients with a pathology of the pancreato-biliary system allows to objectively control the course of the disease and to correct the treatment methods.