Background: Arterial Blood Gas (ABG) analysis is a commonly ordered test to investigate respiratory, circulatory, and metabolic status in traumatic patients with inappropriate perfusion and ventilation situations. Difficult sampling, hemorrhage risk of arterial puncture, and other vascular complications lead us to use saliva sampling as a safer non-invasive approach to evaluate PAO2, PACO2, pH, and HCO3 values. This study was aimed to evaluate the correlation of PAO2, PACO2, pH, and HCO3 values between ABG and saliva gas in traumatic patients under mechanical ventilation. Methods: This was a retrospective cross-sectional study of 18-85-year-old traumatic patients under mechanical ventilation conducted in an academic medical hospital. They were investigated based on age, sex, and ABG values as well their saliva gases values. The Paired t-test, Pearson χ, 2, and Pearson correlation were used to evaluate the correlation between the gases values in ABG and saliva. Data were analyzed using Mann–, Whitney U test and Kolmogorov–, Smirnov test. Results: There were 120 patients including 53 men and 67 women enrolled. None of the factors of arterial and salivary gases were significantly different between men and women. And the amount of these factors is homogeneous in both groups (P <0. 05). The mean factors of arterial PACO2 and HCO3 and saliva PACO2 and HCO3 were significantly different between smokers and non-smokers. Conclusion: The values of salivary gases correlated with these of ABG. This can expand the use of salivary gases analysis as an alternative to ABG analysis in clinical settings to reduce the logistic burden of arterial sampling as well as to better perform ventilator device settings. These results were aligned with previous studies.