Oncological cardiology deals with the prevention, early diagnosis, and treatment of cardiotoxic side effects of modern, multimodal tumor therapy. Tumor therapy includes surgery, radiation therapy, classical or conventional chemotherapy, targeted therapy, and immunotherapy. The side effect scheme of these therapies is complex and partly incompletely characterized. In addition, up to 30 new therapies are approved each year, which poses a great challenge to the field of oncological cardiology. In the current chapter, the individual modalities of tumor therapy with regard to their cardiovascular side effects will be presented and possible diagnostic and therapeutic algorithms will be highlighted.