Both endothelin(ET)-1 and oxidative stress have been the subjects of intense investigation within the cardiovascular field over the past decade and a half, yet little is known about the precise relationship between these important modulators of vascular function. There is a firm evidence that ET-1 can stimulate the production of superoxide via NADPH oxidase activation, and at the same time, reactive oxygen species appear to stimulate ET-1 production. What is less clear is how these changes participate in the pathogenesis of vascular dysfunction. There is mixed evidence on whether oxidative stress plays a role in ET-dependent hypertension, however, a specific influence of ET-induced oxidative stress to reduce vascular reactivity is more convincing. The current review summarizes recent investigations into the relationship between ET-1 and oxidative stress and highlights several areas that require further investigation. © 2005 Bentham Science Publishers Ltd.