PURPOSE: p27Kip1 negatively regulates cell proliferation by mediating cell cycle arrest in Gl and Ki-67 is a reliable cellular proliferative index. Also Bcl-2, an inhibitor of apoptosis, has potential activity toward cell survival. The present study investigated p27Kip1, Ki-67 and Bcl-2 expression in adenoid cystic carcinoma for their usefulness of indicator in tumor progression and aggressiveness. MATERIALS AND METHODS: Formalin-fixed paraffin-embedded surgical specimens were obtained from seventeen patients with adenoid cystic carcinoma. We performed immunohistochemical staining with p27Kip1, Ki-67 and Bcl-2 monoclonal antibodies and compared with patients clinicopathologic features. RESULTS: There were significant correlation between low p27Kip1 expression and high grade and T classification, positive nodal status and perineural invasion and high stages. However, Ki-67 and Bcl-2 expression had no significant differences in clinicopathologic features and p27Kip1 expression. CONCLUSION: p27Kip1 is a good reliable marker of tumor progression and aggressiveness in adenoid cystic carcinomas.