This text presents an update of research advances contributing to a better understanding of relevant clinical models of hypertension, particularly the involvement of the role of oxidative stress in various forms of hypertension as a still emerging subject. This paradigm could be applied to account for blood pressure elevation in the metabolic syndrome, renovascular disease, preeclampsia and chronic kidney disease, among others. These examples are discussed in the light of recent clinical and experimental studies providing a rational base for diagnosis and treatment of the diseases.