Hypertension is a major modifiable risk factor for cardiovascular diseases. After decades of improvement, population surveys demonstrate disturbing downward trends in the rates of awareness, treatment, and control of this disorder in recent years. Over this same time period, there has been a slight increase in the incidence of strokes, and a steady rise in the incidence of end-stage renal disease and the prevalence of congestive heart failure, conditions in which hypertension plays a prominent role. Results of recent studies support the possibility that lifestyle modifications may be effective for prevention of hypertension. Treatment of established hypertension involves lifestyle modifications and drug therapies designed to control blood pressure and reduce overall cardiovascular risk. Both threshold blood pressure levels for initiating drug therapy and goal blood pressure levels with treatment are individually determined based on the presence or absence of additional cardiovascular risk factors and hypertension target organ injury or clinical cardiovascular disease. Recent clinical trials support the value of lower goal blood pressures for patients with diabetes, heart failure, and renal disease. The presence or absence of comorbid conditions often determines specific drug choices. Diuretics and beta-blockers remain the drugs of choice in uncomplicated hypertension. Additional studies confirm the benefits of treating isolated systolic hypertension in the elderly. The Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure provides a practical, evidence-based resource to help health care providers meet the public health challenges of preventing and controlling hypertension.