Introduction: According to the previous studies, about 90% of accidents in the workplace are due to the unsafe behaviors. In this study, the impact of personality traits, as a predictive factor on the unsafe acts was surveyed in a construction project of a car manufacturing company. .Material and Method: In this study, personality traits and unsafe behavior rates were determined using NEO-Five Factor Inventory (NEO-FFI) and safety behavior sampling (SBS) technique. The Spearman correlation coefficient was used. To analyze the acquired results, the total population of the project was 243 people. .Result: The results showed that 31.7% of workers’ behaviors were unsafe behaviors. The correlation between unsafe behaviors and the neuroticism and extroversion were direct and significant (p<0.001). . Conclusion: Assessment of the personality traits could be used as a predictive tool to identify employees with higher rates of unsafe behaviors and helps planning to reduce the accident rates.