Heart transplantation (HTx) has now become an accepted treatment modality for end-stage heart disease. The limited supply of suitable donor organs imposes constraints upon the decision of who should be selected for transplantation. Usually patients are candidates for HTx, who remain NYHA functional class III or IV despite maximal medical therapy. Further criteria are low left ventricular ejection fraction (less than 20%) with heart rhythm disturbances class IIIA-V (LOWN), which are associated with poor prognosis. Additionally, the suffering of the patient and also the course of heart failure are essential for judging the urgency of HTx. Contraindications are absolute in patients with untreated infections, fixed pulmonary vascular resistance (PVR) above 8 WOOD-degrees, severe irreversible kidney and liver disease, active ventricular or duodenal ulcers and acute, psychiatric illness. HTx is relatively contraindicated in patients with diabetes mellitus, age over 60 years, PVR above 6 WOOD-degrees and an unstable psychosocial situation. To prevent rejection of the transplant heart, live-long immunosuppressive therapy is needed. Most immunosuppressive regimes consist of Cyclosporine A and Azathioprine (double drug therapy) or in combination (tripple drug therapy) with Prednisolone. For monitoring of this therapy, control of hole blood cyclosporine A level and white blood count is needed. Rejection episodes can be suspected if there is a greater than 20 mmHg decrease of systolic blood pressure, elevated body temperature, malaise, tachycardia or heart rhythm disturbance. The diagnosis of cardiac rejection can be established by endomyocardial biopsy. Measurement of the voltage of either the surface or intramyocardial ECG, echocardiography with special consideration to early left ventricular filling time as well as immunological methods are additionally used tools. Graft sclerosis as the main risk factor of the late transplant period remains an unsolved problem.