Malignant transformation of the prostate and progression of carcinoma appear to be the consequence of a complex series of initiation and promotional events under genetic and environmental influences. Increased incidence of the condition may be the result of improved detection, greater awareness of the condition, and possibly an increased life expectancy accompanied by a decrease in competing causes of death rather than a true increase in the prevalence of the disease. The marked racial and geographic differences are probably multifactorial, with genetic, environmental, and possibly social influences affecting progression of the disease. Among several risk factors, evidence for the familial inheritance of some prostate cancers is compelling. Dietary influences, hormonal milieu, and the role of environmental carcinogens are currently under intense investigation. As further risk factors are identified, it will become increasingly important to identify individuals at increased risk for the disease. These men should undergo regular evaluation with state-of-the-art methods.