With the aim of morphologically characterizing chronic sialoadenitis in patients with hepatitis C virus (HCV) chronic liver disease, labial salivary gland biopsies from 22 chronic HCV liver disease and from 10 primary Sjögren's syndrome patients were compared. Only focus score (number of aggregates with more than 50 lymphocytes per 4 mm2 of glandular tissue) and grading of inflammation were able to discriminate significantly between the two patient groups. Duct ectasia, acinar depletion, presence of lymphoid aggregates with less than 50 lymphocytes and of lymphoid infiltration within intralobular salivary duct epithelium were evident in both disease groups and appeared to be non-specific, mostly age-related changes. In both patient groups plasma cell and lymphocyte typing showed similar features: T-lymphocytes represented most of the lymphoid population, B lymphocytes were few unless follicles were present. Higher focus score values were associated with a plasma cell switch from an IgA to an IgM and/or IgG predominance. A greater morphological similarity was seen between biopsies of the primary Sjögren's syndrome group and those of female rather than male chronic HCV liver disease patients. Salivary gland tissue in HCV patients responds to damage in a fashion similar to primary Sjögren's syndrome, the only difference being a lesser degree of inflammation.