Arterial allografts, formerly called homografts, came into limited use in the 1940s and 1950s as arterial substitutes. Fresh allografts underwent rapid rejection. Preserved allografts had a longer but still limited clinical life. Allografts demonstrated that arterial replacement was a valid concept and led to the development of synthetic substitutes. Recent renewed interest is based on the need for graft replacements in re-do procedures and in an infected field. Even the best methods of graft procurement and preservation do not preserve normal endothelial and smooth muscle cell functions nor eliminate antigenicity. The biologic and economic costs of immune suppression to obtain a successful allograft for an ischaemic limb are presently unjustifiable. Transplantation between species (xenotransplantation) may be attainable via selective inhibition of the complement system avoiding full immunosuppression now required for organ transplantation. At present allografts may be an acceptable choice for the patient with (1) a critical need for revascularisation and with a life expectancy not exceeding that of the graft, (2) in urgent vascular trauma, and (3) where immunosuppression is contraindicated as in an infected surgical field. Except in most unusual circumstances allografts should not be used for (1) relief of claudication, (2) in the above mid-calf location and (3) anatomic locations where synthetic grafts are superior.