Studies reporting increased mortality in smokers are abundant, but only few have included large numbers of heavily smoking women. Based on three large Danish population studies we calculated median survival in smokers and never-smokers and compared the impact of smoking in men and women. Seventeen thousand six hundred and sixty-nine men and 13,525 women were followed for up to 30 years for all-cause mortality. During follow-up there were 8644 deaths. Large differences in tobacco-exposure between men and women were found, in particular in older birth-cohorts. Despite a smaller accumulated exposure, the impact smoking had on median survival was similar in men and women. Female inhaling heavy smokers (> or = 15 cig./day) lost 9.4 and inhaling light smokers 7.4 years in comparison with female never-smokers. Corresponding loss of life-expectancy in males was 9.2 years and 6.0 years, respectively. In conclusion, this study shows survival prospects in relation to smoking in both men and women in a way that is easily communicated. The results indicate that women who smoke as much as men run a relatively higher risk in terms of reduced life expectancy.