Doppler-shifted ultrasound was used to measure arterial compliance non-invasively in the internal and external carotid pathways of 270 male and 388 female asymptomatic volunteers aged 5 to 90 years. There was a significant decrease in the compliance of both arteries from 5 to 50 years of age (p<0.001), when it then levelled out. Arteries of women were more compliant than those of men at ages 35 to 60 years.