The relationship between blood levels of N-carboxymethyl-lysine (CML) or pentosidine and the severity of microangiopathy was investigated in patients with type 2 diabetes. Blood CML and pentosidine levels were measured by ELISA in 97 type 2 diabetics (46 men and 51 women). CML and pentosidine levels were significantly higher in patients with chronic renal failure than in those with normoalbuminuria, microalbuminuria, or macroalbuminuria (all p<0.05). Among the diabetics without nephropathy (n = 49), blood CML levels were significantly higher in the patients who had proliferative diabetic retinopathy than in those without retinopathy or those who had background retinopathy (both p<0.01). In contrast, blood pentosidine levels showed no significant differences among the three retinopathy groups. These findings suggest that the blood level of CML is related to the severity of both nephropathy and retinopathy, while the pentosidine level is only related to the severity of nephropathy.