BACKGROUND: It is unclear whether immediate dietary effects on blood glucose influence the risk of developing type 2 diabetes. OBJECTIVE: The objective of this study was to examine whether the dietary glycemic index (GI) and glycemic load (GL) were associated with the risk of type 2 diabetes in older adults. DESIGN: The Health, Aging, and Body Composition Study is a prospective cohort study of 3075 adults who were 70-79 y old at baseline (n=1898 for this analysis). The intakes of specific nutrients and food groups and the risk of type 2 diabetes over a 4-y period were examined according to dietary GI and GL. RESULTS: Dietary GI was positively associated with dietary carbohydrate and negatively associated with the intakes of protein, total fat, saturated fat, alcohol, vegetables, and fruit. Dietary GL was positively associated with dietary carbohydrate, fruit, and fiber and negatively associated with the intakes of protein, total fat, saturated fat, and alcohol. Persons in the higher quintiles of dietary GI or GL did not have a significantly greater incidence of type 2 diabetes. CONCLUSIONS: These findings do not support a relation between dietary GI or GL and the risk of type 2 diabetes in older adults. Because dietary GI and GL show strong nutritional correlates, the overall dietary pattern should be considered.