We report two cases of children followed for many years with an original diagnosis of non-A/non-B hepatitis. One child developed serious cirrhosis with portal hypertension. Long-term observation of the course of their hepatic disease provided the diagnosis of cystic fibrosis. These cases demonstrate that cystic fibrosis though rarely presenting with initial hepatic signs, can manifest itself with only long-term hepatic symptoms. We therefore strongly recommend analysis of sweat chloride concentration in cases of hepatic disease of unknown origin.