Transplant physicians and surgeons are familiar with the risks, clinical behavior, and management of cytomegalovirus in transplant recipients. Donor-transmitted viral infections are uncommon but in recent years have brought to light the clinical manifestations of rabies, West Nile virus, and lymphocytic choriomeningitis virus in the early posttransplant period. Later posttransplant, infection with viruses circulating in the community can occur with a number of pathogens, including some vaccine-preventable illnesses such as measles and mumps. Recent advances in molecular microbiology have made it possible to diagnose a growing number of community-acquired viral pathogens infecting transplant recipients. This article reviews some of the emerging and reemerging viral pathogens infecting solid organ and hematopoietic stem-cell recipients, including adenovirus, bocavirus, coronavirus, human herpesvirus-6, lymphocytic choriomeningitis virus, measles, mumps, metapneumovirus, parainfluenza, rotavirus, respiratory syncytial virus, and West Nile virus.