The results of a study that estimated the expected lifetime economic consequences of cigarette smoking for individual smokers are reported herein. The estimates were obtained by combining age- and sex-specific estimates of the incidence-based costs of three smoking-related diseases (lung cancer, coronary heart disease, and emphysema) with estimates of smokers' increased likelihood of developing these illnesses in each remaining year of life relative to nonsmokers. Estimates of the economic consequences of quitting based on these disease cost estimates and on estimates of exsmokers' probability of future disease relative to continuing smokers are also reported. Both the estimates of the economic costs of smoking and the benefits of quitting were calculated separately for men and women between the ages of 35 and 79 who were light, moderate, or heavy cigarette smokers. While the economic costs of smoking varied considerably by sex, age, and amount smoked, they were significant for all groups of smokers. Costs for a 40-year-old man, for example, ranged from $20,000 for a smoker of less than one pack of cigarettes per day to over $56,000 for a smoker of more than two packs of cigarettes per day. The economic benefits of quitting also were found to be sizable for all groups of smokers.