Pleomorphic adenoma is the most common salivary benign tumor, constituting over 60% of parotid gland tumor, 25% of sublingual gland tumor and 50% of minor salivary gland tumor. It is somewhat more frequent in the fourth to sixth decades. The recurrent rate which enforces only a simple enucleation is very high $(20{sim}45%)$. Histologically, it contains the epithelial cell, the myo-epithelial cell and mesenchymal ingredient, which is various aspect. We analyzed clinicopathologically and immunohistochemically the patients(34 cases) who are diagnosed with pleomorphic adenoma in Dept. of Oral & Maxillofacial Surgery, College of Dentisty, Dankook university since 1998. The results are as follow: 1. The incidence of the tumor was most frequent in age 30 to 50. The ratio of male to female was 1:1.43. 2. The most chief complain was a painless mass(94.1%) and the duration time was more than decade in 18 cases(52.9%). 3. Palate(soft & hard palate) was the most occurred site(64.7%). In major salivary glands, the parotid gland was the most frequent site(17.6%). 4. The tumor size was 2 to 3cm on the average. Most of tumors were with capsule(91.2%). 5. Surgical excision was a main treatment method(20 cases, 58.8%) and 14 cases were excised with a glandectomy, 1 case was treated with a partial maxillectomy. Only 1 case of all cases was recurred. 6. Histopathologically, 9 cases(26.5%) were cellular type, 11 cases(32.4%) were intermediate(classic) type and 14 cases(41.1%) were myxoid type. 7. Immunohistochemically, the specimen of all tumors reacted positively to cytokeratin and vimentin marker.