The number of circulating T and B lymphocytes was estimated in 25 patients with biopsy‐verified chronic non alcoholic liver disease. Fifteen of these had circulating HBsAg and/or anti‐HBsAg and 10 were without these markers of HB virus infection. In both groups of patients a significant decrease of T cells and a parallel significant increase in null cells was found, but any difference with respect to T and null cells in patients in the two groups was not observed. Liver biopsies from five of the patients with and four without HB8Ag and/or anti‐HBsAg were studied for the presence of immunoglobulin bearing cells. In three out of five liver biopsies from the HBsAg and/or Ab positive patients and in two out of the four liver biopsies from the HBsAg and anti‐HBsAg negative patients, a heavy periportal infiltration with plasma cells was found. However, the number and classes of the immunoglobulin containing cells could not be correlated either to the histological evaluation of the stage of activity of the liver disease or to the markers for HB virus infection. The immunological findings in the two groups of patients with chronic liver disease seem to be of the same nature and are most likely a consequence of the liver disease and not the caus