Ageing reduces cerebral blood flow (CBF), while mean arterial pressure (MAP) becomes elevated. According to 'the selfish brain' hypothesis of hypertension, a reduction in vertebral artery blood flow (VA) leads to increased sympathetic activity and thus increases MAP. In twenty-two young (24 ± 3 years; mean ± SD) and eleven elderly (70 ± 5 years) normotensive men, duplex ultrasound evaluated whether the age-related reduction in CBF affects VA more than internal carotid artery (ICA) blood flow. Pulse-contour analysis evaluated MAP while near-infrared spectroscopy determined frontal lobe oxygenation and transcranial Doppler middle cerebral artery mean blood velocity (MCA Vmean ). During supine rest, MAP (90 ± 13 versus 78 ± 9 mmHg; P<0·001) was elevated in the older subjects while their frontal lobe oxygenation (68 ± 7% versus 77 ± 7%; P<0·001), MCA Vmean (49 ± 9 versus 60 ± 12 cm s-1 ; P = 0·016) and CBF (754 ± 112 versus 900 ± 144 ml min-1 ; P = 0·004) were low reflected in VA (138 ± 48 versus 219 ± 50 ml min-1 ; P<0·001) rather than in ICA flow (616 ± 96 versus 680 ± 120 ml min-1 ; P = 0·099). In conclusion, blood supply to the brain and its oxygenation are affected by ageing and the age-related decline in VA flow appears to be four times as large as that in ICA and could be important for the age-related increase in MAP.