Benzene exposure is of particular concern because recent research indicates that it can result in chronic toxicity, with an elevated risk of carcinogenesis. Exposure to benzene from automobile exhaust can be an important occupational problem for police. The present study was conducted to estimate risk of Thai traffic police developing cancer due to contact with traffic benzene vapor during daily work. According to the data obtained, the estimated predicted cancer incidence for traffic police is 0.05 case per 70 - year period, simply translated as 1.8 cancer cases per 100,000 traffic police per year. This is clearly a cause of concern and annual check up and monitoring for benzene exposure among traffic police should be set up as part of a program for primary prevention of occupational – related cancer.