Objective:To analyze the relationship between the cytochrome P450 2A13(CYP2A13) gene and tongue cancer. Methods:CYP2A13 mRNA and protein were detected by real-time fluorescent quantitative PCR and western blot respecytively in 26 cases of oral cancer and their corresponding adjacent tissues. Results:CYP2A13 mRNA and protein were expressed in tongue cancer and their surroundings. And the expression of CYP2A13 mRNA and protein in tongue cancer is much lower than in their surroundings (P < 0.05). Conclusion:Down-regulated expression of CYP2A13 may be involved in the development and progression of tongue cancer due to the increase activity of certain carcinogens,and the exact mechanism needs to be further studied.