In recent years, the use of the radial artery as a coronary artery bypass graft has enjoyed a revival. This follows the initial disappointing results with the use of this blood vessel experienced by Carpentier and colleagues in the early 1970s. The improvement in the performance of the radial artery is believed to be caused by improved harvesting techniques and the use of vasodilator drugs. However, compared with other blood vessels used as bypass grafts, little is known about the vascular biology of this artery. The reactivity of the smooth muscle and protection offered by the vascular endothelium are known to be important factors that may determine the suitability of different arteries and veins to act as bypass conduits. The aim of this review is to examine how the properties of the vessel wall may contribute to the performance of the radial artery when used as a coronary artery bypass graft.