Xenotransplantation is a hot topic currently, since the demand for diverse organs is increasing in patients. Among many species, pigs are suitable animals for xenotranplantation as they share many anatomical and physiological characteristics with humans. This review article provides an overview of porcine xenotransplantation and the rejection of pig xenotransplants in primates, and use of genetically modified and cloned pigs in xenotransplantation. It also highlights major target organs in porcine xenotransplantation and virus infection in xenotransplantation.