Information is needed on the treatment of hypertension in children and adolescents with antihypertensive drugs like ramipril. The study will assess the safety and blood pressure effects of several doses of the antihypertensive drug ramipril in children and adolescents age 6-16 years. Approximately 450 children will be given placebo, or 1 of the 3 doses of ramipril. The treatment assigned will be done by chance, like flipping a coin. Approximately 120 study centers throughout the world will participate in the trial.