Hepatic artery thrombosis (HAT) is one of the principal causes of morbidity and graft loss following liver transplantation. There are several risk factors for the development of HAT; technical aspects of the arterial anastomosis are important particularly for early thrombosis, but the improvement of surgical technique has lessened this problem. Apart from technical causes, other risk factors include a variety of conditions such as low donor/recipient age ratio, immunologic factors, clotting abnormalities, tobacco use, and infections. In particular, cytomegalovirus (CMV) infection of endothelial cells has been recently suggested as an infective cause of HAT, as it is known to be followed by a rapid procoagulant response. Thus, latent CMV in an allograft may become activated and promote or contribute to vascular thrombosis. This review evaluates these aspects, focusing on data relating CMV infection or viremia to HAT following liver transplantation.