Background: Systolic blood pressure (SBP) and diastolic blood pressure (DBP) are a multi-factorial traits and significantly heritable. Glutathione S-transferase (GST) enzyme is involved in detoxification of reactive oxygen species. The present study aimed at finding out the association between GSTM1 and GSTT1 polymorphisms and mean arterial pressure (MAP) in Iranian population. MAP, as the important indicator of blood pressure, is calculated by weighted averaging of SBP and DBP. Materials and Methods: we randomly selected 72 healthy individuals from Isfahan Cohort Study (ICS). Polymerase chain reaction (PCR) was done to detect polymorphism of the GSTM1 and GSTT1 genes. The Bayesian Structured Regression model was used, adjusted for sex, age, body mass index (BMI), and smoking status. Results: The results showed that both the GSTT1and GSTM1genotypes deletion had a significant effect on MAP increasing in our samples based on 95% Bayesian credible intervals. Conclusion: This study demonstrated that GSTT1 and GSTM1 gene increase the arterial pressure; hence, it can predict the susceptibility to cardiovascular disease.