Background: Road Traffic Accidents (RTAs) are mostly related with human factor and the health team has focused on it as an important issue worldwide. The main goal of the present study is to assess the association between lifestyle factors and RTAs in Hamadan which is located in west of Iran. Methods: A case-control study was conducted to measure the lifestyle factors affecting RTAs. Two-stage sampling was performed during October and December 2013. The self-reported questionnaire which adjusted by Iranian culture were prepared for the total of 309 adults (103 cases and 206 controls) aged 18-65 years. The reliability of the questionnaire was confirmed by obtaining the Cronbach’s correlation coefficients of 0.89. The data were analyzed by Chi-square and adjusted Logistic regression tests based on age and gender by using SPSS /16 (significant level of 0.05). Result: The Risk of accidents due to daily activity, driving style and perception of traffic laws was 165.1, 656.0 and 308.1 more than the control group. However the difference was not significant. The chances of accident in case group related to stress was about three folds higher than the control group (P<0.001 and OR = 2.958 and 95% CI =265.5, 661.1). Conclusion: Risky lifestyle is a precipitating factor related to RTAs and RTAs can be prevented with controlling this factor in human life.