There is some evidence that plasma insulin and postload plasma glucose may be associated with risk of pancreatic cancer. Glycemic index and glycemic load are measures, which allow the carbohydrate content of individual foods to be classified according to their postprandial glycemic effects and hence their effects on circulating insulin levels. Therefore, we examined pancreatic cancer risk in association with glycemic index (GI), glycemic load (GL), and intake of dietary carbohydrate and sugar in a prospective cohort of 49,613 Canadian women enrolled in the National Breast Screening Study (NBSS) who completed a self-administered food frequency questionnaire between 1980 and 1985. Linkages to national cancer and mortality databases yielded data on cancer incidence and deaths, with follow-up ending between 1998 and 2000. During a mean 16.5 years of follow-up, we observed 112 incident pancreatic cancer cases. There was no association between overall glycemic index, glycemic load, total carbohydrate and total sugar intake and pancreatic cancer risk. In multivariate adjusted models, the hazard ratio (HR) for the highest versus lowest quartile levels of overall GI and GL were 1.43 (95% confidence interval [CI]=0.56-3.65, P(trend)=0.58) and 0.80 (95% CI=0.45-1.41, P(trend)=0.41), respectively. Our data suggest that overall glycemic index and glycemic load, as well as total sugar and total carbohydrate intake, are not associated with pancreatic cancer risk. However, given the limited literature regarding the role of diet in the etiology of pancreatic cancer, particularly with respect to glycemic index/load, further investigation is warranted.