Endoscopic retrograde intrahepatic cholangiograms were evaluated in 107 patients and correlated with intrahepatic diagnoses determined by liver biopsy. Included were normal livers (6), cirrhosis (38), portal fibrosis (14), cholangitis (22), metastases (11), and miscellaneous diagnoses (16). Results suggest that differentiation of the normal from the abnormal intrahepatic biliary system using the endoscopic retrograde intrahepatic cholangiogram is possible, and that certain patterns of abnormality prevail within given disease categories. The cholangiogram in cirrhosis is marked by ductular stenosis, diminished arborization, tortuosity, and approximation of the intrahepatic ducts. Sclerosing cholangitis demonstrates focal stenosis with concomitant ectasias and frequent similar involvement of the extrahepatic system. Chronic cholangitis and portal fibrosis are frequently associated with extrahepatic obstructing lesions and increased intrahepatic ductal caliber, but demonstrate no distinguishing intrahepatic characteristics. Intrahepatic metastases, polycystic liver disease, and primary hepatic neoplasm produce mass effects consisting of ductal displacement, narrowing, and obstruction. The potential of endoscopic retrograde intrahepatic cholangiography in evaluating the intrahepatic biliary tree is significant; specifically in separating normal from abnormal, in distinguishing between intrahepatic processes, and as an adjunct to liver biopsy in determining the extent and location of intrahepatic abnormalities.