Socioeconomic factors play many roles in influencing health including overall health status, lifestyle and occupational exposures, and access to preventive, diagnostic and treatment services. This paper reviews evidence on the geographical distribution of the sex differences in cancer incidence and life expectancy. The analyses reported are at the regional (Italy), continental (Europe), and world-wide scales. In agreement with other contributions on the social epidemiology of cancer, these results indicate that there is a close link between the health of the populations, and socioeconomic and cultural factors, and support the notion that environment contributes strongly to total cancer incidence. Thus, the emphasis for reducing cancer incidence needs to focus more on reducing environmental contributions. In order to improve the health status of the populations, not only applications of the present etiologic knowledge are necessary (for example, it is estimated that around up to 50% of cancers are nowadays technically preventable), but also further research on environmental topics should be stimulated. Within this perspective the indicators of health differences between genders-which are demonstrated to be very sensitive to socioeconomic and cultural factors--can play a very useful role for monitoring environmental factors, and for health planning by agencies and governments.