Available epidemiologic data do not allow targeting of specific populations for prostate cancer screening or early detection programs. Although certain strong factors have been identified (age, race, location), none sufficiently defines high-risk groups in whom recommendations should differ from those of other age-matched patients. Certainly, a strong familial tendency has been identified, but the relative contribution of genetic and environmental factors in these patients remains unclear. Some hypotheses on the pathogenesis of prostate cancer are possible based on the available data. Genetic factors appear to be permissive, as are hormonal influences, which are partially regulated by genetics. Environmental factors appear to be promotional in genetically susceptible men. Dietary fat may also be an important promotional factor in genetically susceptible men. Dietary factors appear to exert some influence by modulating sex hormone concentration. Several factors demand more investigation and understanding of the epidemiology of prostate cancer. The relative frequency of the disease and the increasing death rate from prostate cancer are of concern. The similarities in the incidence of latent prostate cancer among various groups with strong differences in the rate of clinically apparent disease raise significant issues regarding potential lifestyle or environmental promotional factors. Further understanding of the pathogenesis of prostate cancer may allow a refinement and definition of programs for prevention and early detection of the disease.