Background and Purpose: Indigenous people who leave their hometowns and move to the city to earn a living became urban aboriginals. During the process of adapting to urban living situations, they may use various coping strategies such as smoking to overcome their stress. Therefore, it is crucial to provide health education including smoking prevention, increasing knowledge regarding of tobacco hazard, self-efficacy of anti-smoking, and adjusting smoking behavior so as to empower their anti-smoking motivation to prevent lung cancer. The purpose of this study was to explore the effectiveness of an anti-smoking program on urban aboriginals in Taiwan. Methods: A quasi-experimental study design with purposeful sampling was employed. A total of 125 aboriginal subjects were recruited from two local churches at Shu Lin area in northern Taiwan. Subjects were divided into an experimental group (n =64 ) and a control group (n = 61). Both took pre-tests in order to set baseline values, and only the experimental group participated for 3-weeks in the anti-smoking program classes. Both groups took post-tests immediately after the intervention in order to evaluate the immediate effects of the teaching program, and a follow-up test was conducted four weeks after the intervention. Data were analyzed using descriptive statistics, one-way ANCOVA, and repeat measure ANCOVA. Results: After controlling for confounding variables, the results showed that there were statistically significant differences in the self-efficacy of anti-smoking and smoking behavior between experimental and control groups in the immediately post-test and the follow-up test (p < 0.05). However, there was no significant differences in the recognition of hazards of smoking at eiter time point. Conclusions and Implications for Practice: The findings of this study revealed that the anti-smoking program effectively improved self-efficacy of anti-smoking, and decreased the smoking behavior in urban aboriginals. They provide useful information as a reference regarding of aboriginal health promotion to health providers. It is imperative that anti-smoking be reinforced for those regular smokers to prevent induction of lung cancer.