1. Various small/mid-sized conductance arteries have been used for coronary artery bypass grafting as arterial grafts, but unanimous opinion to the best use of these grafts has not been formed. 2. Arterial grafts are not uniform in their biological characteristics. 3. The differences among the arteries may involve the contractility of the vessel. Based on studies of the contractility of arterial grafts, a clinical classification was formed to describe the tendency of vasospasm in the arterial grafts. 4. The differences among arterial grafts also involve endothelial function. This refers to both nitric oxide release from the endothelium, as well as endothelium-derived hyperpolarizing factor-mediated hyperpolarization and relaxation. 5. The difference in the peri-operative behaviour of the grafts and in their long-term patency may be related to different characteristics. These should be taken into account in the use of arterial grafts, some of which are subject to more active pharmacological intervention during and after operation to obtain satisfactory results. The clinical choice of grafts must be based on the general condition of the patient, the biological characteristics of the graft, the anatomy of the coronary artery, the match between the coronary artery and the graft and the technical considerations, including antispastic management.