Data from 149 cases with pancreatic cancer and 363 control subjects in Utah were obtained from proxy respondents to assess the associations between dietary intake and the development of pancreatic cancer. After adjusting for cigarette smoking status and alcohol and coffee consumption, we observed that foods containing large amounts of fat from all sources increased risk of pancreatic cancer in men [odds ratio (OR), 3.41; 95% CI, 1.59-7.29]. Further division of fat by source of food showed that high intake of bacon and sausages (OR for upper tertile, 2.77; 95% CI, 1.34-5.72) as well as large intakes of fatty foods other than meat or dairy products (OR for upper tertile, 2.80; 95% CI, 1.33-5.89) increased risk of pancreatic cancer in men; high levels of intake of red meat, chicken, fish, and dairy foods did not increase risk of pancreatic cancer in either men or women. In women, fat from nonmeat and nondairy sources also increased risk of pancreatic cancer (OR for upper tertile, 3.44; 95% CI, 1.35-8.78). Although no protective effect was observed among men who consumed large amounts of fruits, vegetables, or high fiber foods, we did observe a protective effect in women for these foods (OR for upper tertile of fruit consumption, 0.37; 95% CI, 0.18-0.81; OR for upper tertile of vegetable consumption, 0.32; 95% CI, 0.13-0.74; and OR for upper tertile of fiber consumption, 0.28; 95% CI, 0.12-0.67). Findings from this study support the hypothesis that diets high in fat contribute to the development of pancreatic cancer.(ABSTRACT TRUNCATED AT 250 WORDS)