Background: Relatively few children require treatment for hypertension; those who do usually have underlying renal or other organ system disease. However, the awareness of childhood hypertension has been increasing, leading to a greater need for sound pediatric data on which to base treatment decisions. Objective: This article reviews the currently available pediatric data on the use of angiotensin-converting enzyme inhibitors, beta-adrenergic antagonists, calcium channel blockers, and other classes of antihypertensive medications in children, highlighting the areas in which better data are needed. Methods: Selected publications on the therapy of childhood hypertension were reviewed. Emphasis was placed on studies involving newer agents and on multicenter, controlled trials. Results: The amount of data available regarding the efficacy and tolerability of antihypertensive agents in children is limited but growing. Recent multicenter trials spurred by the 1997 US Food and Drug Administration Modernization Act frequently lack important pharmacokinetic data specific to the pediatric use of these drugs. Conclusions: Well-designed pediatric trials are needed not only to demonstrate drug efficacy in children, but also to elucidate drug kinetics and meticulously document whether the adverse effects that occur in children are different from those that occur in adults.