Hypertension is the most important modifiable risk factor for stroke. There is clear and ample evidence of benefit for treating elderly hypertensive subjects up to the age of 80 with systolic pressures of over 160mmHg either alone or in combination with diastolic pressures over 90 mmHg. There is also now evidence of benefit in terms of the secondary prevention of stroke. There is no strong evidence of any clear differences between the different drug classes, apart from alpha-blockers being less effective than diuretics. There is the suggestion from a meta-analysis of comparative trials that calcium-channel blockers may be better in terms of stroke reduction but further data are required and they may have disadvantages when considering the prevention of cardiac events. The benefits of treating individuals with pressures below 160 mmHg systolic or aged 80 or more remain unproven.