Six patients requiring intermittent haemodialysis for chronic renal failure underwent construction of an arteriovenous fistula using modified human umbilical cord vein allografts. Three grafts soon showed degenerative changes and were removed--2 thrombosed and 1 became infected. Satisfactory haemodialysis was achieved with the remaining 3 grafts. Two grafts are currently patent at 9.5 and 11 months respectively, while another graft became aneurysmal after 8 months, requiring its removal.