Abstract: Endotheiial cell activation is a major obstacle to successful xenotransplantation. The activated phenotype is largely based on the transcriptional induction of a number of genes and their products. Due to the large number of new gene products in activated endotheiial cells, it is not feasible to target each of them individually for therapeutic intervention. A common factor important for the induction of many, if not all, genes induced upon endotheiial cell activation if NF‐KB. It is thus a reasonable target for inhibition if one is to attempt to inhibit endotheiial cell activation genetically. Donor animals for xenotransplantation are amenable to genetic manipulation and we believe that transgenic animals carrying several transgenes will be the standard of future experimental and clinical xenotransplantation.