Cardiotoxicity is a serious complication of anti-tumorous treatment. Cytostatics can cause a number of undesirable side-effects such as arrhythmias, angina pectoris, acute myocardial infarction, sudden death, cardiac failure. The probably most serious cardiotoxicity is chronic cardiac failure after treatment with anthracyclines. Interest in the diagnosis, monitoring and treatment of cardiotoxicity revealed new findings of cardiac complications after various cytostatics, high-dosage chemotherapy and transplantation of haematopoietic cells. Prospective paediatric studies provided evidence of the serious character of late cardiotoxicity of anthracyclines. The authors review the most frequent cardiac complications of anti-tumorous treatment. They emphasize in particular the toxicity of anthracyclines and its possible prevention.