Forty-eight patients, or 24 percent of the total number of 200 patients with overt or latent diabetes, were found to have bilateral asymptomatic enlargement of the parotid glands. Most of these patients were unaware of that the enlargement was present. In seven patients the observation of parotid enlargement was made before the diagnosis of diabetes by glucose tolerance test. I believe that the association between parotid gland enlargement and diabetes mellitus reported here is very striking. The enlargement of the parotid glands is easily overlooked since it is asymptomatic; therefore, palpation of the glands is essential. The results indicate that asymptomatic enlargement of the parotid glands is not uncommon in diabetes mellitus and that a search for diabetes should be made in all patients exhibiting enlarged asymptomatic parotid glands.