Background/Aim: Hypertension is one of the main cardiovascular risk factors, and it may be responsible for the excess morbidity and mortality in postmenopausal women. Endothelium-dependent dilation of conduit arteries is reduced in women after menopause, as shown by the reduced flow-mediated dilation (FMD) of the brachial artery. The aim of this study was to evaluate changes in FMD during and following a 6-month-long treatment with increasing doses (10, 20 and 40 mg) of quinapril in hypertensive postmenopausal patients. Methods: A multicenter, open-label, non-comparative, baseline control study in 61 postmenopausal outpatients. Results:The mean baseline FMD (% ± SD) of the 53 patients in the intent-to-treat population (patients with at least one FMD evaluation) was 2.83 ± 1.24%; FMD of the 51 subjects on 10 mg quinapril daily was 5.58 ± 2.179%; FMD of the 52 patients on 20 mg quinapril was 7.06 ± 2.31%, and FMD of the 53 subjects on 40 mg daily was 8.07 ± 2.57% (p < 0.001 for each dose, compared to baseline). Conclusion: Ourresults confirmed that quinapril improves endothelial function at all examined doses as measured by FMD. Modulation of the renin-angiotensin system may act as a target for reducing cardiovascular risk in postmenopausal hypertensive women.