Pancreatic cancer is one of the most lethal neoplasms. Incidence in the United States has remained fairly stable over the past 25 years, with about 25,000 cases annually. Almost 100% of cases are fatal. Incidence in the developed world parallels that in the United States. Incidence in undeveloped nations is lower but may be underreported. Worldwide incidence is about 185,000 cases per year. There are no striking environmental risk factors, and geographic variation is less than with other gastrointestinal cancers. The most significant risk appears to be cigarette smoking, with a risk ratio of about 2. Alcohol and coffee consumption have been reported as possible risks in some (but not in most) studies. Diet is probably a significant factor, but is difficult to evaluate quantitatively. Other putative associations, including diabetes, probably are unimportant.