BACKGROUND AND OBJECTIVE Alteration of salivary gland secretion is one of the consequences of diabetes. In a recent study on the submandibular gland of diabetic subjects, we found changed expression of statherin, a salivary protein of fundamental importance in preserving tooth integrity, whose reduction was related with the high incidence of oral diseases in patients with diabetes. The goal of this report is to extend the study to human parotid gland and to compare the effects of diabetes on statherin expression with those previously described in submandibular gland. MATERIALS AND METHODS Fragments of parotid glands obtained from diabetic and non-diabetic patients were fixed, dehydrated, embedded in Epon Resin and processed for the immunogold histochemistry. The staining density was expressed as number of gold particles per μm(2) and statistically evaluated. RESULTS AND CONCLUSIONS In all samples, statherin reactivity was specifically localized in secretory granules of acinar cells. The statistical analysis showed that labelling density was significantly lower in diabetic than in non-diabetic parotid glands and that diabetes affects protein expression at identical extent in parotid and submandibular glands. The results strengthen the hypothesis that a reduced statherin secretion may be responsible for the higher incidence of oral disorders in diabetic subjects.