Tobacco use is an important risk factor related with human health, which will increase the cost of medical services. Basic unit police officers occupy an important position in the community as both enforcers of the law and role models for appropriate behaviors. High job stress was found to be associated with high-risked behaviors such as alcohol consumption, tobacco use, drug abuse, and suicide. The purpose of this study was to determine the association of job stress with smoking behaviors among basic unit police officers. A cross-sectional study design was conducted in 2009. 387 basic unit police officers were recruited using cluster sampling from 24 police substations of Taipei County. Self- administrated questionnaires were used to collect: a) demographic characteristics (gender, age, marital status, level of education, the official rank, seniority, experience of threaten with their life on duty), b) smoking behaviors, c) job stress. Internal reliability of job stress scale was reached with cronbach’s α of .94. Data were analyzed using Chi-Square test, T-test, logistic regression with SAS version 10.1. The results in this research were found that the current smoking rate was 50.66％; gender, age, marital status, level of education, the official rank, seniority were significantly associated with smoking behaviors among basic unit police officers. The percentage of environmental tobacco exposure among non-current smokers was 62.90％. Gender, marital status, seniority were significantly associated with environmental tobacco exposure. Among current smokers, the percentage of quitting smoking was 56.02％. Age was significantly associated with attempt of quit smoking. In job stress, external job stress was the highest subscore, followed by individual job stress and internal job stress. Current smokers had higher individual job stress than others. However, none of these job stresses were associated with the prediction of smoking behaviors. In conclusion, the smoking prevalence was higher in basic unit police officers than general population. The development of smoking prevention program is needed to reduce tobacco use for health promotion among basic unit police officers. Keyword: Basic unit police officers, Smoking behavior, Job stress