Phenotypic expression of sialylated Lewis(x) antigen by means of the monoclonal antiserum SNH3 was studied in 87 livers, which included normal and steatotic livers and livers with chronic persistent and chronic active hepatitis, alcoholic hepatitis, allograft rejection, focal nodular hyperplasia, hepatocellular carcinoma, cholangiocarcinoma, metastatic carcinoma, cirrhosis of various causes (autoimmune, alcoholic, viral, drug induced, Wilson's disease, and primary biliary cirrhosis). The biotin-streptavidin-peroxidase method was used on formaldehyde-fixed, paraffin-embedded sections. Sialylated Lewis(x) antigen was not demonstrated in normal livers. Hepatocellular expression in a diffuse or perinodular honeycomb pattern was seen in cirrhosis, irrespective of cause. Sialylated Lewis(x) antigen was also observed in hepatocytes around metastatic carcinoma in the absence of inflammation, cirrhosis, or regeneration. Some bile ductules, most likely ductular hepatocytes, but not bile ducts, expressed sialylated Lewis(x) antigen. Sialylated Lewis(x) antigen was seen diffusely in fibrolamellar hepatocellular carcinoma, focally in other hepatocellular carcinomas, and either focally or diffusely in cholangiocarcinomas.