Background and aims. Cigarette smoke can induce oral cancer by its free radicals and oxidative damage. Salivary anti-oxidants system is believed to have an important role in defense mechanisms against oxidative stress. This study was compared total antioxidant capacity (TAoC) of saliva in smokers and nonsmokers. Materials and methods . In this cross-sectional study, 30 male smokers with mean age of 45.23 years and 30 nonsmokers with mean age of 45.30 years participated. Unstimulated whole saliva samples were collected in the morning in two groups by spitting method. TAoC of saliva was measured with the special kit in two groups at the same time. Statistical analysis was performed by covariance test. Results. The mean salivary TAoC in nonsmokers (0.741±0.123 U/ml) was higher than that in smokers (0.529±0.167 U/ml). This difference was statistically significant (P<0.001). Conclusion. Smoking can alter salivary antioxidant capacity.