SUMMARY The cytoplasmic bodies in hepatocytes thought to indicate possession of the Z allele for a1-antitrypsin deficiency were found at necropsy in 10 of 64 adults with cirrhosis, four of nine with hepatic fibrosis, and four of 15 with hepatocellular carcinoma. They were also found in six of 76 adults with severe panacinar emphysema, and in four of a control series of 110 adults with neither emphysema nor liver disease. The association of the bodies with each of the three liver diseases was statistically significant, but the association of the bodies with emphysema was not. It is considered probable that heterozygous (PiMZ) a,-antitrypsin deficiency is associated with an increased incidence of cirrhosis, hepatic fibrosis, and hepatocellular carcinoma. 28 June 1976 records were examined for cases of hepatic fibrosis, hepatoma, and cirrhosis other than that due to large duct obstruction: 64 cirrhotic livers (11 with hepatocellular carcinoma), nine fibrotic livers (1 with hepatocellular carcinoma), and three livers with hepatocellular carcinoma but neither cirrhosis nor fibrosis were found; blocks of non-neoplastic liver were available from all cases (76), and blocks of hepatocellular carcinoma from the 15 cases with hepatocellular carcinoma. The control series consisted of blocks of liver from 110 consecutive adult necropsies in which there was neither clinical nor pathological evidence of liver disease or emphysema.All the liver blocks were formalin-fixed and paraffin-embedded. Sections were cut at 4 ,um: one section from each case was stained with haematoxylin and eosin, one for reticulin, and one with periodic acid Schiff after diastase. The diagnosis on the liver was checked and confirmed in each case. The characteristic acx-antitrypsin bodies were not stained in the haematoxylin and eosin preparation but were seen as rounded, sharply-defined, solid bodies staining strongly with periodic acid Schiff after diastase, in the cytoplasm of hepatocytes, predominantly in the periportal cells. Bodies up to at least 3 ,um diameter were found in each positive case, and frequently bodies up to 15,um diameter were present. In addition, sections were cut at 4 ,um from the liver blocks of all cases with cirrhosis, hepatic fibrosis or hepatocellular carcinoma, of all cases showing cxlantitrypsin bodies on periodic acid Schiff staining, and of 27 cases of emphysema randomly selected from those without cti-antitrypsin bodies oa periodic acid Schiff staining: these were mounted on albumin-132