Endothelial dysfunction is the common early stage of most cardiovascular afflictions. The endothelium is considered the main mediator of vascular homeostasis via its vasodilator, anti-inflammatory and anticoagulant properties. Among the different endothelial-derived mediators, nitric oxide is produced by nitric oxide synthase and has a critical role in regulating endothelial function. Physiological and pathological processes such as aging and diabetes mellitus are associated with disturbances of endothelial function which, at least at the earliest stage, can be reversed by lifestyle and pharmacological intervention to reduce the risk of incident cardiovascular diseases. Among dietary strategies, curcumin is a cheap and safe nutraceutical polyphenol with proven antioxidant and anti-inflammatory properties. Given the important role of such processes in the development of endothelium dysfunction, a role for curcumin in the prevention or treatment of this condition has been hypothesized. This review summarizes the available literature on the beneficial role of curcumin on vascular endothelial function.