Immunological studies performed in 12 patients with chronic calcifying pancreatitis show significant increase in serum concentrations of IgA and IgM. Presence of autoantibodies to smooth muscle, mitochondria, antinuclear, gastric parietal cells and IgG was not frequent. Immune complexes were detected in the sera of 11 patients. Normal numbers of B lymphocytes and a significant decrease in T-active and total T lymphocytes were observed in peripheral blood. These results suggest an immunologic participation in chronic calcifying pancreatitis and may explain the persistence and progressive nature of the disease.