A tissue graft is disclosed that includes a decellularized umbilical vessel having a luminal surface and an ablumenal surface, wherein the decellularized umbilical vessel is prepared by an automated dissection process. The decellularized umbilical vessel has not been substantially cross-linked. In one method of use, the decellularized umbilical vessel is capable of having at least one cell type seeded at least a portion of at least one of the luminal and ablumenal surfaces thereof. A process of preparing the tissue graft, methods of using the tissue graft, and kits which contain the tissue graft are also disclosed.