Purpose: The purpose of this work was to evaluate the expression of GRP78 as a prognostic indicator of aggressiveness in salivary gland tumors and to relate its expression with the biological behavior of the salivary gland tumors. Material and Method: 80 cases of salivary gland tissues were collected as paraffin embedded blocks: 30 benign cases (15 pleomorphic adenoma and 15 Warthin's tumors) and 45 malignant cases (15 carcinoma ex pleomorphic adenomas, 15 mucoepidermoid carcinomas in addition to 15 adenoid cystic carcinoma). Additionally, 5 normal salivary gland tissues. Using GRP78 antibody, an immunohistochemical investigation was done for all specimens. Results: The mean area percent of immunoexpression was greatest in malignant variants of salivary gland tumors, followed by benign variants of salivary gland tumors and the least value recorded in normal salivary gland tissue. Conclusion: According to the current study, GRP78 is considered as a useful marker for diagnosis of malignancy of salivary gland.