Follow-up immunological studies in 27 patients with acute pancreatitis of known etiology showed a significant elevation in the level of circulating immune complexes (IC), a significant inhibition in migration of leukocytes (with direct LMT) of patients and a significant decrease in the percentage of T-active, T-total peripheral lymphocytes and in the absolute count of peripheral T cells. Elevated circulating IC levels could been detected 3-4 weeks after the onset of acute pancreatitis. These immunological changes have still been demonstrated in a number of patients 7-14 months after recovery. We have found similar immunological alterations in patients with chronic pancreatitis as well. The possible causes and role of these long-term existing immunologic abnormalities are discussed.