Abstract: The efficacy of xenotransplantation of porcine pancreatic islets to different "im-munologic privileged sites "in rats, such as ventricle of cerebrum(VC), thymus(TH), under re-nal capsule(URC), and portal vein(PV)was investigated.The results demonstrated that porcine pancreatic islets transplanted into the four sites could control the hyperglycemic state in the rats and maintain normal blood glucose concentration for a period of time without using any immuno-suppressant.The average functional survival of xenografts in VC group was longer than the other three groups(TH, URC, and PV), with the difference being significant(P<0.05), but there was no significant difference among the other three groups(P>0.05).It was also observed that the curves of blood glucose declination and elevation in PV group were the steepest, while the blood glucose level in CV group declined relatively late, and increased smoothly and slowly.It is suggested that all of these"immunologic privileged sites"are relative.With the view of immunolo- gy, ventricle of cerebrum is a more appropriate site for xenotransplantation of porcine pancreatic islets.In terms of normal physiological function, portal vein is the site where porcine islets can play its role fastest.