The normal ageing process of the brachial artery (BA) wall is of specific interest since it is often selected as a model artery in studies of vascular function. With echo-tracking ultrasound, diameter, absolute diameter change and intima-media thickness (IMT) were registered in 60 healthy subjects, 21-86 years (30 males) at a proximal, upper third and distal arterial site along the upper arm. Blood pressure was recorded non-invasively and the distensibility coefficient (DC) was calculated. The diameter at the proximal site increased with age from 5.5±0.2 in the young to 6.9±0.3 mm (p<0.01) in the elderly subjects, concomitantly as IMT increased from 0.40±0.01 to 0.65±0.03 mm (p<0.001). The diameter at the other sites was similar in the young and elderly subjects, whereas IMT increased slightly with age. At the proximal site DC decreased dramatically from 40.7±2.2 to 10.1±0.8 10^-3/kPa (p<0.001) with age, while hardly no change was seen at in the distal upper arm. The principal transit zone between elastic to predominantly muscular artery behaviour seems to be located within the proximal part of the brachial artery, emphasizing the importance of carefully defining the arterial examination site.