Heart transplantation has emerged as the therapy of choice for selected patients with life-threatening, irremediable heart disease. Infectious complications are frequent, but are no longer the leading cause of death. Late infections (particularly viral infections), however, are still a threat to long-term graft survival in these patients. Bacterial infections are the most common, particularly of the respiratory tract, which usually appear in the first month or after one year following transplantation in patients with previous COPD. Catheter-related infection is also common, whereas postoperative mediastinitis is much less frequent. The overall incidence of fungal infections has decreased considerably in recent years (2%-15%), but associated mortality remains high. Pulmonary aspergillosis is the most common. Cytomegalovirus is the most important pathogen in heart transplantation, currently affecting 7%-35% of patients. Antiviral prophylactics and pre-emptive therapy have reduced the incidence of acute CMV disease, but the potential role of this microorganism as a cofactor in allograft vascular disease, the most common cause of death in these patients, is a cause for concern. Toxoplasmosis, a particularly severe entity in heart transplant recipients, has decreased with the use of routine prophylaxis in seronegative recipients.