Cigarette smoking is the single most preventable cause of premature death in the United States. An estimated 390,000 smoking-attributable deaths in the United States occurred in 1985, and more than 434,000 deaths occurred in 1988; in 1988, an estimated 1,198,887 years of potential life lost (YPLL) before age 65 were attributed to smoking. To estimate the national impact of cigarette smoking on mortality and YPLL, calculations were performed using the Smoking-Attributable Mortality, Morbidity, and Economic Cost (SAMMEC) software. This report summarizes the results of this analysis.