The Stroke Prevention Research Unit was founded in 2000. The main areas of research are the secondary prevention of stroke, the aetiology of ischaemic and haemorrhagic stroke, hypertension, genetics of stroke, vascular cognitive impairment, imaging in TIA and stroke, and biomarkers, with broader interests in the epidemiology of coronary and peripheral arterial disease and in the risks and benefits of aspirin. The Unit’s most clinically important results have been: i), better targeting of intervention in patients with symptomatic carotid stenosis; ii), demonstration of the very high risk of major stroke after TIA and minor stroke and derivation of effective tools for emergency triage; iii), an 80% reduction in the early risk of major stroke by urgent use of preventive treatments after TIA/minor stroke; iv), demonstration of the role of variability in blood pressure and episodic hypertension in the aetiology of stroke and vascular dementia, and in explaining differences in effectiveness of antihypertensive drugs; v), demonstration of the effects of aspirin on incidence and mortality due to cancer and several other non-vascular diseases.