Hypertension (HTN) is a major cause of stroke, left ventricular hypertrophy, congestive heart failure, arteriosclerosis, end-stage renal disease, and peripheral vascular disease. Oxidative stress and its constant companion, inflammation, play a critical part in the pathogenesis of many acute and chronic illnesses including HTN and its long-term complications. There is compelling evidence that oxidative stress, inflammation, and HTN are involved in a self-perpetuating vicious cycle which, if not interrupted, culminates in progressive target organ injury and dysfunction. This article is intended to review the available evidence for the role of oxidative stress and inflammation in the pathogenesis of HTN. In addition, evidence will be presented to demonstrate the role of HTN in the pathogenesis of oxidative stress and inflammation. Finally, evidence for participation of tissue angiotensin system in the vicious cycle of oxidative stress, inflammation, and HTN will be presented, and the approach to treatment of HTN-associated oxidative stress will be discussed.