Background : Recently several reports accentuated effects of blood pressure variability(BPV) in cardiovascular complications. BPV has been shown to depend on autonomic vascular modulation and changes in arterial stiffness. Diabetic patients are particularly prone to have deranged autonomic control and arterial distensibility and adverse cardiovascular consequences. Methods and Results : We analyzed the records of ambulatory blood pressure measurement of 69 patients with diabetic history longer than 5 years and 84 controls. Ambulatory BPV was assessed as standard deviation(SD) and coefficient of variation(CV). BPV was significantly increased in patients with diabetes than without diabetes independent of mean blood pressure(mean BP SD 12.5짹3.5 vs 10.8짹2.7 p=0.001, mean BP CV 0.12짹0.03 vs 0.10짹0.03 p=0.001, mean BP 105.3짹12.5 vs 104.9짹11.0 p= 0.954). Systolic and mean BPV was significantly correlated with duration of diabetic history(SBPSD and MBPSD, r=0.393 and 0.182, p=0.001 and 0.024). Conclusions : These results demonstrate that BPV is increased in patients with diabetes than non-diabetic patients independent of mean blood pressure.