Our immunohistochemical study shows that atrial natriuretic peptide (ANP) is present in both human fetal and adult parotid gland. In the fetuses ANP is localized in cell clusters, while in adult parotid gland, the ANP is seen only in the wall of intra- and extralobular ducts. The results suggest that ANP might play a role in the differentiation of the parotid gland similarly as in brain and that during fetal growth ANP may play a role in the regulating the secretion of primitive salivary fluid, even if acini are still not developed.