Serum level of γ-globulins was studied on 100 blood donors, 30 patients with chronic hepatitis, 51 patients with liver cirrhosis and 43 patients with primary hepatoma in regard to hepatitis-associated antigen (HAA). Blood donors with HAA had an increased level of γA as compared with subjects lacking HAA. In chronic hepatitis, no difference was recorded between the positive and the negative group. Liver cirrhosis patients with HAA had a raised level of γM and hepatoma patients with HAA seemed to have a raised level of γ-globulins, as compared with patients lacking HAA.