Accumulation of advanced glycation end products in vessel walls may increase arterial stiffness and/or thickness, contributing to a high incidence of cardiovascular disease (CVD) in patients with diabetes. We investigated whether serum concentrations of pentosidine, a well-defined advanced glycation end product, are associated with arterial stiffness or thickness in patients with type 2 diabetes. Pentosidine was measured in sera from 98 patients with type 2 diabetes and 61 age-matched control subjects by a competitive enzyme-linked immunosorbent assay. Arterial stiffness was evaluated by heart-brachial and brachial-ankle pulse wave velocities (PWVs) measured using an automatic device. Arterial thickness was determined ultrasonographically as carotid intima-media wall thickness (IMT). Serum concentrations of pentosidine were significantly higher in patients with diabetes than in control subjects (64.4 +/- 21.0 vs 22.8 +/- 7.0 microg/L; P < .0001). In patients with diabetes, serum pentosidine correlated positively with heart-brachial PWV (r = 0.304; P < .01) but not with brachial-ankle PWV. Serum pentosidine also correlated positively with carotid IMT in patients with diabetes (r = 0.300; P < .01). Serum pentosidine concentrations were significantly higher in patients with diabetes with CVD than in those without (72.3 +/- 23.7 vs 62.3 +/- 19.8 microg/L; P = .0453). By multivariate analysis, only age (partial coefficient = 0.308; P < .05) and serum creatinine (partial coefficient = 0.328; P < .01) retained significant influence on serum pentosidine. After adjustment for renal function, carotid IMT still correlated positively with serum pentosidine (partial coefficient = 0.2736; P = .021). In conclusion, serum pentosidine was positively associated with both arterial stiffness and thickness and CVD in patients with type 2 diabetes.