BACKGROUND: Diabetic autonomic neuropathy has a significant negative impact on survival and quality of life in type 2 diabetic patients. Especially cardiovascular autonomic neuropathy (CAN) is clinically important, because of its correlation to cardiovascular death. Therefore, we investigated the prevalence of CAN in Korean type 2 diabetic patients. METHODS: 1798 type 2 diabetic patients, 727 males and 1071 females, visited Diabetes Clinic at St. Vincent Hospital, Korea, were included from January 2001 to December 2005. Clinical evaluation, laboratory test and assessment of diabetic complication were completed. Standard test for CAN were performed: 1) heart rate variability (HRV) during deep breathing (E/I ratio) 2) Valsalva maneuver 3) 30:15 ratio 4) blood pressure response to standing. CAN score was determined according to the results of the test as following: 0 = normal, 1 = abnormal. RESULTS: Mean age and diabetic duration of patients were 56.7 +/- 10.9, and 9.4 +/- 7.5 years. Normal and abnormal CAN were detected in 815 (45.3%) and 983 (54.7%) of the patients, respectively. Abnormal E/I, valsalva, and 30:15 ratio were found in 333 (18.5%), 717 (39.9%), and 546 (30.4%) patients, respectively. Age, diabetic duration, postprandial hyperglycemia, HbA1c, C-reactive protein, and microalbumuria levels were significantly different between normal and abnormal CAN groups. 49 (6.0%) patients of normal and 100 (10.2%) patients of abnormal CAN group showed previous attack of stroke (P = 0.004). In addition, diabetic foot was more frequent in patients with CAN (normal vs. abnormal, 14 (1.7%) vs. 73 (7.4%), P < 0.05). CONCLUSION: CAN is frequently found in Korean type 2 diabetic patients. It was associated with diabetic duration, uncontrolled diabetes, increased albumin excretion rate, presence of retinopathy, postprandial hyperglycemia.