The remission and cure rates for cancer have been remarkably improved over the past few decades. At the same time, cardiovascular complications related to chemotherapy and radiotherapy emerge as one of the major factors that influence the prognosis or quality of life, and thus increase the demand for cardiologists to be more deeply committed to medical care of cancer patients. Under such circumstance, “Onco-Cardiology” or “Cardio-Oncology” attracts much attention worldwide as a new discipline for research and clinical activities. However, we currently have insufficient amount of clinical data in this field, and little is known about the molecular pathogenesis. This session will present cutting-edge basic, epidemiologic, and clinical research, as well as new approaches and movements in medical healthcare services, in Onco-Cardiology/Cardio-Oncology. We will discuss what cardiologists can do and what cardiologist should do to protect cancer patients and cancer survivors from cardiovascular complications.