Aim. - Nuts are rich in unsaturated fatty acids as well as other bioactive constituents. The present study investigated the association between nut consumption and the incidence of type 2 diabetes mellitus (T2DM) in a Middle Eastern population. Methods. - The study was conducted within the framework of the Tehran Lipid and Glucose Study (TLGS), in which 1984 participants (920 men and 1064 women) free of DM, aged >= 20 years, were followed from phase III (2005-2008) to phase V (2011-2014). Dietary data were obtained from valid and reliable food-frequency questionnaires at baseline. Using multiple logistic regression, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated, with adjustments for age, gender, BMI, serum cholesterol and triglycerides, smoking and energy intake. Results. - Study participants' means +/- SD of age and of BMI were 40.1 +/- 13.1 years and 27.0 +/- 4.8kg/m(2), respectively. The median SE of their total daily consumption of nuts was 1.19 +/- 0.11 servings. After 6.2 +/- 0.7 years of follow-up, 150 cases of T2DM were confirmed. On comparing those who consumed >= 4 servings/week with those who consumed <1 serving/week, the age-/energy-adjusted OR of incident T2DM for total nut consumption was 0.64 (95% CI: 0.36-1.12; P for trend = 0.03). In a fully adjusted model, nut consumption was associated with a lower risk of T2DM, and the ORs (95% CIs) of risk for those consuming 2-3.99 and >= 4 servings/week of nuts were 0.51 (0.26-0.97) and 0.47 (0.25-0.90), respectively, compared with those consuming <1 serving/week (P < 0.001 for trend). Conclusion. - Our findings suggest that consuming >= 4 servings/week of nuts reduced the risk of T2DM compared with < 1 serving/week. (C) 2016 Elsevier Masson SAS. All rights reserved.