We report two elderly patients with seronegative Sjögren syndrome who showed benign swelling of the pancreas on computed tomography. Immunostaining of the biopsied lip tissue or serum examination confirmed an increase in production of IgG4, leading to a diagnosis of autoimmune sclerosing pancreatitis (ASP) as a cause of the asymptomatic swelling of the pancreas. Sicca symptoms and ASP spontaneously improved in one patient, and the other responded well to oral prednisolone. Seronegative Sjögren syndrome and ASP can concurrently occur as a clinical manifestation of the IgG4-related systemic disorder, particularly in elderly subjects, and, in such a case, corticosteroid may be a potent therapeutic option.