Dietary energy-dense foods predispose to obesity and may be associated with risk of type 2 diabetes; therefore, the aim of our study was to investigate the association between dietary energy density [DED] and the risk of type 2 diabetes. In this matched nested case-control study, 178 new onset cases of diabetes were selected from among participants of the Tehran Lipid and Glucose Study, and followed for over 9 years. Each case was randomly matched with 3 controls from among participants who had not developed diabetes. Dietary intakes were determined using a valid and reliable food frequency questionnaire. DED was calculated as energy intakes [kcal] from foods and beverages divided by the weight [grams] of foods. The mean ages of participants were 43 +/- 6.5 and 44.5 +/- 12 years, in women and men respectively. Individuals with higher DED had higher calories, total fat, carbohydrate and processed meat intakes and lower fruit and vegetable intakes in men and women [P<0.05] . Energy density was positively associated with incident diabetes in women, after adjustment for diabetes risk factors and total calorie intake [OR: 2.28, P trend=0.02] or total fat intake [OR: 2.15, P trend=0.03] , an association which was not significant in men. In this nested case-control study, there was positive association between DED and risk of type 2 diabetes in women