Consuming vegetables and fruits can reduce the risk for cardiovascular diseases. Nutraceutical products have been increasingly used to retard the onset of cardiovascular complications and to treat postmenopausal symptoms. Cranberries are rich in antioxidant polyphenols, such as flavanoids and related phenolic acids. In this study, we aimed to examine whether consumption of cranberry juice could ameliorate endothelial dysfunction in an animal model of estrogen deficiency. Female Sprague-Dawley rats, weighted 200-230 g, were anaesthetized using sodium pentobarbital (40 mg kg⁻¹ body weight, i.p.) under aseptic conditions and then ovariectomized via the abdominal route. Sham-operated rats were used as controls. The rats were divided into three experimental groups: sham-operated, ovariectomized, and ovariectomized rats receiving cranberry juice. Changes in vascular reactivity (constriction and dilatation) in aortas, carotid arteries, and renal arteries from all three groups were studied in organ bath or on myograph. The expression level of endothelial nitric oxide synthase (eNOS), Akt, angiotensin 1 receptor and nitrotyrosine were detected by Western blot. The endothelium-dependent relaxation to acetylcholine was significantly reduced in the three types of isolated arteries from ovariectomized rats and the impaired endothelial function can be partially prevented by acute treatment with angiotensin 1 receptor blocker. Chronic consumption of cranberry juice significantly ameliorated endothelial dysfunction due to estrogen deficiency in ovariectomized rats. The vascular tension developed by the addition of phenylephrine was higher in ovariectomized rats than in control rats. This increased contraction was attenuated in rats receiving cranberry juice. Last, there is also an increased oxidative stress, as indicated by nitrotyrosine level, which was restored by cranberry consumption. Chronic consumption of cranberry juice (i) increased phosphorylation of eNOS at ser1177 without affecting the total aortic protein contents of eNOS and Akt, and (ii) decreased protein expression for angiotensin 1 receptor in aortas. The results of the present study suggested that chronic oral administration of cranberry juice to ovariectomized rats clearly augments the bioavailability and function of endothelial nitric oxide in systemic blood vessels via stimulating eNOS phosphorylation and inhibiting expression and/or function of angiotensin 1 receptor-mediated vascular dysfunction. The active ingredients in cranberry juice responsible for restoring endothelial function remain to be further elucidated.