The mortality experience of a population of smokers is compared with that of a population of nonsmolcers using various methods of statistical analysis. As numerous studies have indicated previously, the mortality rates for smokers are consistently higher than for nonsmolcers. From the point of view of aging studies, cigarette smoking (since it involves an appreciable percentage of the population and is generally believed to be related causally to the increased incidence of disease) can be regarded as the principal environmental factor which has been identified as accelerating aging in nonspecific human populations in Western societies. Also, since the data show that smoking is associated with an earlier onset of the main age-associated diseases, this suggests that smokinginduced life shortening proceeds via similar mechanisms at the molecular or tissue level as those of normal aging.