Smoking is a strong risk factor for myocardial infarction (MI) and sudden coronary death, but not for angina pectoris that is not complicated by a MI. Even light cigarette and pipe and cigar smokers run an increased risk for MI and sudden coronary death. Smoking potentiates other risk factors such as lipid abnormalities and hypertension. Smoking increases blood pressure acutely, but smokers have generally had lower blood pressures than nonsmokers in epidemiologic studies. Smoking adversely affects the prognosis in patients who have suffered a MI and those with angina pectoris. Of great importance regarding community risk of smoking are the many light and moderate smokers. These persons should be addressed more vigorously in intervention efforts.