Epidermal growth factor is a single-chain polypeptide consisting of 53 amino acids and has a potent mitogenic activity that stimulates proliferation of various normal and neoplastic cells through the interaction with its specific receptor(epidermal growth factor receptor, EGFR). Pleomorphic adenoma is the most common salivary benign tumor and histologically, it contains the epithelial cell, the myo-epithelial cell and mesenchymal ingredient, which is various aspect. Adenoid cystic carcinoma is an infiltrative malignant salivary gland tumor with three different histological patterns: cribriform, tubular or solid. The tumor cell structure composed of modified myoepithelial cell, and basaloid cell. In this study, we used an immunohistochemical technique to investigate the expression of EGF in 6 specimens of adenoid cystic carcinoma and 10 specimens of pleomorphic adenoma taken from patients treated at Dept. of Oral and Maxillofacial Surgery, Dankook University. The results were as follows. 1. In pleomorphic adenoma, ductal structure and scattered spindle cells in hyalinized stroma, disclosing myxoid stroma and hyalin, cartilage formation were observed. Immunohistologically, weak EGF expression in ductal structure and negative in stromal area were observed. 2. Cribriform type of adenoid cystic carcinoma showed numerous pseudocyst surrounded by dark small neoplastic cells in the back-ground of fibrous connective tissue and moderate EGF expression of dark cells adjacent to pseudo lumen in cribriform pattern, while weak expression in other most cells. 3. Tubular type of adenoid cystic carcinoma showed numerous ductal pattern surrounded by two layered neoplastic cells in the back-ground of fibrous connective tissue and strong EGF expression in luminal cells of ductal structure, while weak expression in outer cells. From the results obtained, we suggest that EGF is mainly biosynthesized in cells forming duct like structures of tubulo-ductal type or cribriform adenoid cystic carcinoma and it may play a role, as a cell mitogen in adenoid cystic carcinoma growth.