Salivary duct carcinoma (SDC) was first described by Kleinsesser in 1968 and was classified as an independent entity by the 1991 Revised World Health Organization. It is a rare but highly malignant tumor. We reviewed pathology in 49 cases of salivary adenocarcinoma, and diagnosed 6 cases as SDC. All had a rapidly enlarged mass in the parotid gland. All were men, and 4 involved facial palsy and metastasis to cervical lymph nodes. Fine needle aspiration biopsy was conducted in 3 cases, but none was diagnosed as SDC. Two had chemotherapy, but showed no effect. All underwent surgery, but only 1 survived more than 4 years. Immunohistochemically, none showed s-100 protein. Four showed PCNA and p53 protein. Highly positive cells of PCNA and p53 were found around comedo necrosis.