BACKGROUND: This study was undertaken to investigate that intima-media thickness and plaque of the carotid artery, as measured by high resolution B-mode ultrasonography, can be used as predictors for occurrence of clinical macrovascular complication in type 2 diabetes patients. METHODS: High resolution B-mode ultrasonographic examination was performed in 39 type 2 diabetes, including 16 diabetes with macrovascular complication, and in 18 non-diabetic control subjects. Concurrently serum total cholesterol, HDL cholesterol, triglyceride, lipoprotein (a), HbA1c, C-peptide levels and body mass index (BMI) were measured and history of hypertension, smoking, duration of diabetes and occurrence of macrovascular complication during the last 6 months were investigated. RESULTS: 1) Significant differences in common carotid IMT (0.72+/-0.08 mm, vs 0.93+/- 0.26 mm), existence of atherosclerotic plaque (50%, vs 69%), plaque number (0.5+/- 0.86, vs 0.69+/-2.37) and carotid stenosis (0%, vs 18%) were found between control and type 2 diabetes (p<0.05). 2) Significant differences in age (67.63+/-4.30, vs 60.6+/-12.0), lipoprotein (a) (63.65+/- 32.2 mg/dL, vs 35.22+/-34.74 mg/dL), common carotid IMT (1.08+/-0.27 mm, vs 0.82+/- 0.20 mm), existence of atherosclerotic plaque (87.5%, vs 56.5%), plaque number (2.88+/-3.16, vs 0.91+/-1.02), end diastolic ventricular septal thickness (10.82+/-1.88 mm, vs 8.76+/-2.92 mm) and end diastolic left ventricular posterior wall thickness (10.79+/-1.60 mm, vs 9.1+/-2.56 mm) were found between type 2 diabetes patients with macrovascular complication and without macrovascular complication (p<0.05). 3) Age (r=0.363, p=0.023), hypertension (r=0.32, p=0.047), carotid plaque existence (r=0.377, p=0.018) and plaque number (r=0.662, p=0.000) showed a correlation with the IMT in type 2 diabetes. 4) Most common involving site of atherosclerotic plaques was carotid bulb and more extensive involvement was showed in type 2 diabetes with macrovascular complication than without macrovascular complication. 5) The sensitivity of common carotid IMT (> control mean IMT + 2 SD; >1.22 mm) for prediction of macrovascular complication in type 2 diabetes patients was 25%, the specificity 95.7%, the positive predictive value 80%, the negative predictive value 61.8%. 6) The sensitivity of existence of carotid plaque for prediction of macrovascular complication in type 2 diabetes patients was 87.5%, the specificity 60.9%, the positive predictive value 60.9%, the negative predictive value 87.5%. CONCLUSION: Increases in IMT and plaque of the carotid artery, as measured by high resolution B-mode ultrasonography, can be used as predictors for occurrence of clinical macrovascular complication in type 2 diabetes patients.