In the United States, incidence of and mortality from pancreatic cancer increased for several decades earlier in this century but have tended to level off in recent years. Rates increase with age and are higher in blacks than in whites and higher in males than in females. No consistent differences by socioeconomic status or by geographic location in the United States have been identified, although international variation and differences in migrants have been observed. Thus, both genetic and environmental factors may be playing significant roles in the development of pancreatic cancer. Cigarette smoking increases the risk of pancreatic cancer, but the strength of this association is much less than for lung cancer or other smoking-related cancers. Epidemiologic studies of the effect of alcohol consumption on pancreatic cancer largely show no relationship, and the results for coffee consumption indicate little, if any, association. Human studies have suggested positive associations with meat consumption and carbohydrate intake and a protective effect of dietary fiber and consumption of fruits and vegetables. Results of a number of occupational studies are suggestive of increased risk associated with some exposures but are not fully consistent. Thus, much progress has been made in the last two decades in identifying risk factors, but much epidemiologic work is needed to identify and reduce putative exposures.