Smoking is a risk factor for acute myocardial infarction; paradoxically, many studies have shown a lower post-infarct mortality among smokers. There are some important differences between smokers and non-smokers, which might explain the observed difference in mortality: smokers have less multivessel disease and atherosclerosis but are more thrombogenic; thrombolytic therapy seems to be more effective among smokers; smoking might result in an increased out-of-hospital mortality rate, by being more arrhythmogenic; and smokers are on average a decade younger than non-smokers at the time of infarction, and have less concomitant disease. Adjusting for these differences in regression analyses shows that smoking is not an independent risk factor for mortality after acute myocardial infarction. The difference in age and risk factors are responsible for the lower mortality among smokers.