Smoking cessation decreases mortality among the elderly. Participants in the Leisure World Cohort Study initiated in 1981 were followed until death or January 1, 1991. The 8869 women and 4999 men (median age = 73 years at initial survey) contributed 105,952 person-years of follow-up; 4002 had died. All-cause mortality rates were highest among current smokers; compared with never smokers the age-adjusted relative risks (and 95% confidence intervals) were 1.67 (1.46, 1.92) for women and 1.95 (1.66, 2.30) for men. Current smokers had increased risks of coronary heart disease, other cardiovascular disease, and cancer. Risk of death from smoking-related cancers continued to be high among former smokers, although lower than the risk among current smokers. Relative risks of mortality from cancer and cardiovascular disease increased with the number of cigarettes smoked per day and with a decreasing number of years since cessation of smoking.