The endothelial function was estimated in diabetic patients (N=189) using a dedicated instrument Endo-PAD 2000 and expressed as the reactive hyperemia peripheral arterial tonometry index (RHI). The mean RHI of the overall cohort was 1.56±0.37, and 68.3 % of the patients were under 1.67, the lower limit of normal subjects. A multiple regression analysis indicated that the RHI was significantly correlated with the systolic blood pressure at examination (P<0.001) and the presence of peripheral arterial disease (PAD) estimated by the ankle brachial pressure index (<0.9). A multiple comparison test adjusted by the systolic blood pressure also showed that the RHI of patients with PAD was significantly lower than that of patients without macroangiopathy. The RHI was also significantly correlated with urine albumin excretion (ACR) in select patients with ACR less than 150 mg/gCr. These data indicate that the RHI estimated by the Endo-PAD 2000 is largely affected by the systolic blood pressure at examination and suggest that the RHI is correlated with the presence of PAD and mild albuminuria.