PIP: This article highlights the major conclusions of the US Department of Health and Human Services' 1983 report on the association between cigarette smoking and coronary heart disease (CHD) and other forms of cardiovascular disease. The report estimates that up to 30% of deaths from CHD can be attributed to smoking (170,000 deaths in 1980), making smoking the most important known modifiable risk factor for CHD. Smokers have a 70% greater CHD death rate than nonsmokers, and those who smoke 2 or more packs/day have an almost 200% greater CHD mortality rate than nonsmokers. Although the effect of smoking is independent of the other major risk factors for CHD, it interacts with elevated serum cholesterol and hypertension to substantially increase the CHD risk beyond the sum of the individual components. When 1 factor is present, the risk approximately doubles; with 2 factors present, the risk is 4-fold greater; and when all 3 are present, the CHD risk is 8-fold greater than when none of the 3 factors are present. A synergistic relationship has also been noted between cigarette smoking and oral contraceptive (OC) use, with women who use both having a 10 times higher risk of myocardial infarction than women who use neither. The OC-smoking combination is further associated with increased risk of subarachnoid hemorrhage. Smoking is the major modifiable risk factor for atherosclerotic peripheral vascular disease as well. Smoking cessation substantially reduces the risk of CHD. The proportion of adults who regularly smoke in the US has been reduced from 43% in 1966 to 33% in 1980. Intervention studies and trials suggest that the effectiveness of smoking cessation programs increases when multiple methods such as individual counseling, group sessions, and media campaigns are combined with reinforcement and follow-up.