Purpose: The purpose of this study was to investigate the stages of change in smoking cessation after a Coronary Artery Bypass Graft(CABG) and to identify the related factors. Methods: The subjects (n=157) were patients who underwent a CABG in a university hospital from March 1998 to October 2005 and were smokers before the CABG. Data was collected viachart review and a telephone interview, and analyzed with descriptive statistics, $X^2$ test, one-way ANOVA, and Kruskal-Wallis procedure by the SPSS/PC win 12.0 program. Results: The subjects smoked for an average of 34 years (21 cigarettes per day) before surgery. Eleven percent of the subjects were in pre-contemplation, 6.4% in contemplation, 13.5% in preparation, 4.5% in action, and 64.5% in the maintenance stage. Nicotine dependence and self-efficacy were different among the groups with different stages of change in smoking cessation. Nicotine dependence was the lowest (p=0.00) and self-efficacy was the highest (p=0.00) in the maintenance stage. The number of subjects in pre-contemplation and contemplation significantly increased 6 years after surgery(p=0.05). Conclusions: To implement effective smoking cessation interventions for CABG patients, the intervention should be developed to accommodate individual readiness for smoking cessation, especially so for those who had a CABG more than 6 years previously.