['Atherosclerosis in patients with type 2 diabetes has been linked to oxidative stress. NADP[1]:quinone oxidoreductase 1 (NQO1) plays a key role in cellular antioxidant defense. Recent reports suggest that highly expressed and inducible endogenous NQO1 from cardiovascular cells may act as a potential superoxide scavenger. We examined the relationship between the risk of NQO1 C609T polymorphism and carotid artery atherosclerosis in patients with type 2 diabetes.', 'We recruited 601 (Seoul set) and 233 (Koyang set) unrelated patients with type 2 diabetes from independent groups. The C609T variant of NQO1 was genotyped by Taqman RT-PCR. Mean and maximum carotid intima-media thickness (IMT) and carotid artery plaques were measured by high-resolution ultrasonography.', 'Patients with the T allele exhibited a higher prevalence of atherosclerotic plaques than non-T allele carriers in both sets (Seoul set vs. Koyang set, p=0.021, p=0.023, respectively). After adjusting for age, sex, duration of diabetes, systolic blood pressure, body mass index, current smoking, HDL-cholesterol, LDL-cholesterol and HbA1c, subjects with the T allele had a significantly higher risk of carotid artery plaques (Seoul set vs. Koyang set, OR=1.65, p=0.015; OR=2.00, p=0.037, respectively) than subjects with the CC genotype.'] Is the C609T variant of NQO1 associated with carotid artery plaques in patients with type 2 diabetes?