Fecal bile acid and fecal fat were determined in 18 normal subjects and 22 patients with chronic pancreatitis, and the relation of fecal bile acid excretion to exocrine pancreatic dysfunction was studied. In chronic pancreatitis fecal bile acid was approximately three times that of control subjects, and large amounts of primary bile acid were detected. A significant correlation between fecal bile acid excretion and bicarbonate secreted from the pancreas was found. This evidence of bile acid malabsorption was not observed until bicarbonate output was < 0.05 mEq/h/kg. A slight correlation between fecal bile acid and absorption rates of fat was demonstrated. These results suggest that bile acid malabsorption observed in chronic pancreatitis is related to an impairment of pancreatic bicarbonate secretion.