Background and Objectives : Risk factor modification is the key preventing subsequent cardiac events after heart attack. This study was designed to investigate the gap between preventive guidelines and clinical practice in smoking patients. Materials and Methods : The study was carried out in smokers who admitted with heart attack at 5 university hospitals in Korea. Total 275 patients who were on the regular follow up for more than one year after myocardial infarction (MI) were randomly selected and enrolled in this study. We investigated the change of smoking behavior and adherence rate to the ACC/AHA guidelines for the secondary prevention in patients with coronary artery disease, at the time of and 1 year after the event. Results : The patients consisted of 267 males (97.1%) with a mean age of 57.0짹11.2 years. The patients achieved target goals at one year were as follow; smoking cessation 51.3%, blood pressure 83.9%, HbA1C 32.7%, lipid 65.5%, body mass index 50.5%. Only 58.8% of the patients attempted to quit smoking and 45% of them started smoking again within 1 month after discharge. There was no previous smoking pattern(smoking onset age, amount and duration) associated with success or failure of quitting smoking. From the multivariate logistic analysis including smoking patterns and clinical characteristics, severity of coronary artery disease was the only independent predictor for smoking cessation (RR 1.230, p=0.022). On the other hand, continuous smoking was not the independent predictor of re-intervention or myocardial infarction at 1 year. Conclusions : Only small percentage of MI patient adherent to guidelines for the secondary prevention. Furthermore, quite a few of smokers failed to quit smoking, therefore we need an effective patient education system to help them. KEY WORDS : Acute myocardial infarction, smoking, risk factors