Large-scale clinical trials of antihypertensive drugs that have shown a reduction in morbidity and mortality used the classic step-care treatment design, initiating treatment with a diuretic. Long-term morbidity and mortality reports comparing the newer classes of agents with the traditional antihypertensive agents have not been completed. A recent meta-analysis of 13 randomized, controlled clinical trials of hypertension showed that 18 elderly people, but two to four times as many younger people, needed to be treated for 5 years to prevent one cerebrovascular or cardiac event. Any head-to-head comparisons of one class of antihypertensive agent with another in the prevention of vascular complications will require very large cohorts, even of elderly people, to show a difference. Such trials are ongoing or being planned, but their results will not be available before the next century.