Concentrations of immunoreactive trypsin (IRT) and pancreatic and salivary amylase activities were measured in 22 patients with primary Sjögren's syndrome (SS) and in 13 patients with secondary SS. Nineteen of the 22 patients with primary SS had above-normal IRT, and six had above-normal pancreatic isoamylase activity. Six of the 13 patients with secondary SS had above-normal IRT; none had above-normal isoamylase activities. Serum IRT and pancreatic isoamylase were correlated significantly (r = 0.7; p less than 0.0001). Above-normal values for IRT and pancreatic isoamylase were more frequent in patients who had SS for longer than 10 years, but were not related to the presence of salivary gland autoantibodies or to salivary isoamylase activity. We conclude that the concentration and activity of pancreatic enzymes are frequently abnormal in SS; that the abnormality is greater and more frequent in patients with primary SS; and that it increases with the duration of the disease.