The purpose of the study was to detect cases of Sjögren's syndrome among newly diagnosed untreated patients with non-Hodgkin's lymphoma and, furthermore, to identify in such cases clinical and serologic features known to occur more frequently in Sjögren's syndrome patients who evolve into lymphoma. Accordingly, thirty-three cases of newly diagnosed non-Hodgkin's lymphoma, prior to any treatment administration, were thoroughly studied for evidence of Sjögren's syndrome. Immunophenotyping for T and B cells and kappa and lambda light chains was concomitantly performed on both lymphomatous tissues and minor salivary glands. There were 5 patients with T cell and 28 with B cell lymphoma of various histologic subtypes and grades. Two of the latter (7.1%) had a positive for Sjögren's syndrome minor labial salivary gland biopsy, positive responses to the specific questionnaires for both eye and mouth dryness and abnormal Schirmer's and rose Bengal eye tests, substantiating the diagnosis of Sjögren's syndrome. Both were male with lung and stomach non-Hodgkin's lymphoma respectively, enlargement of the lacrimal glands, monoclonal gammapathy of the IgM kappa type and, one of them had high titer and of fine speckled pattern positive antinuclear antibodies and anti-Ro(SSA) and anti-La(SSB) antibodies in his serum. A monotypic infiltrate with kappa light chain restriction, identical to that in the lymphomatous tissue of these two patients, was present in their minor salivary gland biopsy as well. Such a finding was not encountered in any of the remaining patients. Although our sample is relatively small, our results confirm the relationship between Sjögren's syndrome and non-Hodgkin's lymphoma, looked at from the opposite direction. Obviously, studies involving larger populations would be more definitive, regarding the issue of what percentage of this lymphoma patients originates from Sjögren's syndrome.