OBJECTIVES: This study examined whether smokers recognize that smoking is likely to shorten their lives and, if so, whether they understand the magnitude of this effect. METHODS: People's expectations about their chances of reaching age 75 were compared with epidemiological predictions from life tables for never, former, current light, and current heavy smokers. Data on expectations of reaching age 75 came from the Health and Retirement Survey, a national probability sample of adults aged 50 through 62 years. Predictions came from smoking-specific life tables constituted from the 1986 National Mortality Followback Survey and the 1985 and 1987 National Health Interview Surveys. RESULTS: Among men and women, the survival expectations of never, former, and current light smokers were close to actual predictions. However, among current heavy smokers, expectations of reaching age 75 were nearly twice as high as actuarial predictions. CONCLUSIONS: These findings suggest that at least heavy smokers significantly underestimate their risk of premature mortality.