The study aimed to determine some factors related to flow-mediated vasodilatation of brachial artery in postmenopausal women with metabolic syndrome by 2D ultrasound. A descriptive cross-sectional method was performed in 190 postmenopausal women with metabolic syndrome aged 48 to 60 years at Thai Nguyen National Hospital. Mean age was 57.3 ± 3.3, BMI 24.4 ± 2.3, systolic blood pressure 140.5 ± 11.8, diastolic blood pressure 86.0 ± 9.7, insulin 16.8 ± 16.5, blood glucose 7.6 ± 3.3, estradiol 20.5 ± 6.4 and testosterone 24.7 ± 6.4. Systolic blood pressure ≥140 mmHg, fasting glucose disturbances, and diabetes were risk factors associated with decreased flow-mediated vasodilatation of brachial artery. Estradiol and testosterone concentrations in quartiles 3 and 4 were associated with a higher risk of decreased flow-mediated vasodilatation of brachial artery compared with groups with estradiol and testosterone concentrations in the first quartile.