Infection transmission from donor to recipient is a dreadful complication in transplantation. Although bacteremia was previously detected in 5% of donors without negative impact on recipient outcome, the current expansion of graft pool requires consideration of the infectious risk associated with suboptimal donors. This study aims to evaluate the incidence and risk factors of infection in unselected cadaveric liver donors, the occurrence of microorganism transmission to recipient and its influence on patient survival. Results of microbiologic cultures obtained before harvesting in intensive care unit (ICU) and routinely at harvesting from 610 consecutive liver donors were retrospectively analyzed. Evidence for bacterial and fungal transmission to the recipient was searched for in each culture-positive donor. One or more cultures were positive in 293 donors (48%), while bacteremia was present in 128 (21%). Culture-positive and bacteremic donors were of significantly older age and had longer ICU stays. At multivariate analysis, an ICU stay of 3 or more days was the only significant predictor of donor infection. Although 1-year patient/graft survival rates were not influenced by donor culture positivity, pathogen transmission occurred in 11 cases with high recipient 1-year mortality (45%). In those 11 cases, median donor age was 74 years, significantly much older than that of the other culture-positive donors. In conclusion, donors with a prolonged ICU stay are at increased risk of infection, while older donor age is associated with pathogen transmission to the recipient. Adequate donor maintenance and careful microbiologic surveillance and treatment, especially of elderly donors, may limit transmission of donor infection. Liver Transpl 12:1253-1259, 2006. © 2006 AASLD.