Hypertension is very common, occurring in over 50% of older people, and is a major risk factor for death from stroke, congestive heart failure and coronary heart disease. Antihypertensive drug therapy is the mainstay of treatment for hypertension. OBJECTIVE: The purpose was to review the existing evidence from systematic reviews and meta-analyses on the benefits of drug treatment of hypertension in older people and to compare the quality and results of individual reviews. METHODS: Studies included were systematic reviews of drug therapy for hypertension in older adults with a substantial literature search, appropriate inclusion criteria, validity assessment, details of studies, and appropriate pooling. The databases searched were Medline, Cochrane Library, HealthStar, Embase, and DARE, years 1993-1999. Quality assessment and data extraction were performed independently by two reviewers. Outcomes of interest were overall mortality, stroke morbidity and mortality, CHD morbidity and mortality, and cardiovascular morbidity and mortality. RESULTS: Ten systematic reviews met inclusion criteria. Antihypertensive drug therapy was associated with significant reductions in overall mortality, and mortality due to stroke, coronary heart disease (CHD), and all cardiovascular causes. To prevent one cerebrovascular event in the over 60s would mean treating 50 patients for five years. The quality scores for the ten reviews ranged from 2.4 to 6.9 (0 to 7 possible), with the majority of the studies achieving a score of five or greater. The results of the meta-analyses showed similar reductions in morbidity and mortality, with the exception of those analysing individual drugs or age group. CONCLUSIONS: Treatment of hypertension in older people reduces cardiovascular morbidity and mortality by approximately 33%. The quality differences between systematic reviews did not alter the results.