Objectives: The purpose of the study was to test the applicability of the Theory of Planned Behavior(TPB) to Korean adult smokers in order to obtain an enhanced understanding of their smoking-cessation intention and to establish strategies for effective smoking-cessation interventions at the community clinic. Methods: The data came from a survey that was conducted on adult male smokers who visited the smoking-cessation clinic at H community clinic in Korea from January to November in 2006 (N=434). Included in the survey were questions asking core variables and salient belief variables dictated by TPB. A structural equation model was established using TPB and data were analyzed to examine the applicability of the theory to the understanding of the structure of variables leading to intention. Results: The analysis of the structural model revealed that the study model was statistically significant(p<.001), suggesting the high validity of TPB in explaining the structure of the data. Among the relationships in the model, negative behavioral beliefs were not significant(p>.05), and negative control beliefs and subjective norm were significant(p<.05) but not as highly as other variables in the model(p<.001). Conclusion: TPB was useful in understanding smoking-cessation intention of smokers who visited community clinic to stop smoking. More specific strategies for counseling and education need to be developed to enhance attitude and perceived behavioral control (self-efficacy) toward smoking-cessation intention, such as emphasizing health benefits of quitting smoking, and eliciting values and life principles that can help increase the intention to stop smoking.