Introduction: Many patients who are hospitalised for acute ischaemic episodes stop smoking; however, many of them relapse and resume smoking again within three months from their hospitalisation. The aim of this study was to study the factors that might affect smoking resumption in patients who have suffered an acute coronary syndrome. Methods: We studied 420 patients, active smokers at the time of admission, who were hospitalised for an acute coronary episode. The patients' data (history, risk factors, smoking habits) were retrieved from their medical files. During their hospitalisation they were asked to stop smoking and to attend the smoking cessation clinic to be advised about this. The patients were followed for one year and logistic regression analysis was used to evaluate the independent predictors of smoking resumption and continuation. Results: Of the total patient population, 280 (66.67%) visited the smoking cessation clinic and followed a special programme. Most relapses were recorded during the first 3 months of follow up, after which time 223 (53.1%) were still smoking, compared with 256 (61.43%) at 1 year. Independent predictors of smoking resumption were: non-participation in the smoking cessation programme (odds ratio, OR: 4.32, p=0.0007); the use of antidepressants (OR: 2.28, p=0.01); a history of vascular disease (OR: 2.32, p=0.03); a history of chronic obstructive pulmonary disease (OR: 1.35, p=0.001; and a decree of nicotine dependency >8 on the Fagerstrom scale, as recorded in questionnaires (OR: 1.42, p=0.04). Conclusions: Smokers with acute coronary syndromes should be encouraged to participate in special secondary prevention programmes. Smoking cessation clinics contribute significantly to a reduction in smoking in this group of patients.