West Nile virus is a mosquito-borne RNA Flavivirus infection transmitted to humans and other vertebrates, mainly by the Culex species of mosquito. Since the mid-1990s, the frequency and apparent clinical severity of West Nile virus outbreaks have increased. We report the case of a patient who developed West Nile virus encephalitis shortly after undergoing cardiac transplantation. Clinicians should be aware of the possibility of West Nile virus infection in transplant recipients and in patients receiving blood transfusions.