Alpha 1-antitrypsin has been examined in formalin-fixed, paraffin-embedded liver specimens from Greek patients with cirrhosis (35 cases) and hepatoma (55 cases) by peroxidase-antiperoxidase (PAP) method. Ring-like AAT globules were found in the non-neoplastic cells in 12% of the cases of hepatoma and in 11% of the cases of cirrhosis. Atypical globules were seen in neoplastic cells in 5.4% of the cases of hepatoma and in 17% of the cases of liver cirrhosis. A diffuse fine granular pattern of AAT distribution was present in 31% of the cases of hepatoma in the neoplastic cells and in 27% of those in the non-neoplastic cells. The relatively high incidence of ring-like AAT-globules, and of atypical globules in cases of hepatoma and cirrhosis is not in agreement with the extremely low gene frequency of Z allele in a Greek population of patients with cirrhosis and hepatoma. Thus, there is some doubt whether AAT-globules in the liver represent a histopathologic marker of genetically determined AAT deficiency. A relationship between AAT deposits and the degree of differentiation of hepatoma was noted in this series. AAT-positive cells were found in 55% of moderately differentiated, in 29% of highly differentiated and in 20% of poorly differentiated hepatomas.