This study investigated the potential transmission of porcine endogenous retrovirus (PERV) to solid-organ transplant recipients and abattoir workers in contact with pigs. Blood samples were obtained from volunteer healthy blood donors (Group A; n=33); pig-breeding farmers who had undergone a liver transplant (Group B; n=14); and pig abattoir workers (Group C; n=49). A second blood sample was obtained 1 year after the first sample from 10 of the abattoir workers (Group D). Tests included investigation for PERV-DNA, PERV-RNA, pig-specific mitochondrial DNA, a quantitative detection of PERV nucleic acids, and antibodies to PERV by two different Western Blots. All polymerase chain reaction and Western Blots assays were negative for PERV or antibodies to PERV. Therefore, the risks of cross-species transmission of PERV appear to be negligible for immunocompetent individuals and allotransplant recipients, even if they are in close and repeated contact with live pigs or pig tissues.