Reduction of large artery distensibility has several adverse consequences for the cardiovascular system. This paper reviews the evidence obtained by measuring distensibility through quantification of changes in arterial diameter versus blood pressure changes at large elastic and middle size muscle artery sites. Evidence is available that arterial distensibility is reduced in conditions as varied as hypercholesterolemia, hypertension, diabetes and congestive heart failure. In some conditions (e.g. hypertension) the alterations are not uniformly distributed in arteries of different structure and size whereas in others (e.g. diabetes and heart failure) they are widespread. In diabetes evidence is available that distensibility changes occur early in the course of the disease. Evidence is also available that in all above conditions treatment can improve arterial distensibility thereby reversing the initial abnormality. This appears to be due to a variable combination of structural and functional factors. Technical ability to determine their precise role in distensibility changes in humans is limited, however.