Focal lymphocytic infiltration of the submandibular gland was investigated on the autopsy cases. The materials examined were 340 cases without the collagen diseases and 28 cases with collagen diseases. Of the 28 cases with collagen diseases, 20 were systemic lupus erythematosus, 2 with the coexistence of systemic, lupus erythematosus and Sjögren's syndrome, 4 with rheumatoid arthritis and 2 with progressive systemic sclerosis. Among the cases without the collagen diseases, the focal lymphocytic infiltration was seen in 154 cases (74%) of 209 males and in 94 cases (71%) of 131 females. All 28 cases with collagen diseases had a focal lymphocytic infiltration. The incidence of grade 3 or severe infiltration was 4% in the males and 14% in the females in the cases without the collagen diseases, 65% in the 20 cases with systemic lupus erythematosus, 50% in the 4 cases with rheumatoid arthritis and 50% in the 2 cases with progressive systemic sclerosis. No cases of very severe infiltration were found, which were seen in the classical Sjögren's syndrome, in both cases with and without the collagen diseases. Hyperplastic change in the ductal cells, which can be called an epimyoepithelial island, was found in 23% of the cases with collagen diseases. These observations suggest that the focal lymphocytic infiltrations is a focal sign of the immunologic disorder of the submandibular gland in the collagen disease.