Hypertension is increasingly common with advancing age and a risk factor for all kinds of cardiovascular complications. Moreover, cardiovascular disease is a major cause of morbidity and mortality in the elderly. The Swedish Trial in Old Patients with Hypertension (STOP-Hypertension) was set up by the Swedish Hypertension Society to investigate the value of antihypertensive treatment in the elderly. In this placebo controlled randomised prospective study 1,627 men and women aged 70-84 years with a supine blood pressure > or = 180/105 mmHg (and/or) but not isolated systolic hypertension participated. Three beta-blockers and one diuretic were used as blood pressure lowering agents and the average follow-up in the study was 25 months (3,390 patient-years). Administration of active antihypertensive therapy, reduced supine blood pressure from 195/102 mmHg to 167/87 mmHg at longest follow-up in comparison with placebo. A majority of the patients needed combined treatment to reach the goal blood pressure (160/95 mmHg). Associated with a fall in blood pressure were significant reductions in all cardiovascular primary endpoints (-40%, p = 0.0031), in fatal and non-fatal stroke (-47%, p = 0.0081) and in total mortality (-43%, p = 0.0079). In addition to the substantial effects on primary endpoints active treatment also showed clinically relevant effects on secondary endpoints (e.g. heart failure). The impact on cardiovascular morbidity and mortality with antihypertensive treatment in this elderly cohort was greater than previously seen in middle-aged hypertensive patients, with maintained tolerability and a favourable cost-effectiveness ratio. Finally, women benefited from treatment at least as much as men.