Modern treatment strategies have led to improvements in cancer survival, however, these gains might be offset by the potential negative effect of cancer therapy on cardiovascular health. Cardiotoxicity is now recognized as a leading cause of long-term morbidity and mortality among cancer survivors. This guideline, authored by a pan-Canadian expert group of health care providers and commissioned by the Canadian Cardiovascular Society, is intended to guide the care of cancer patients with established cardiovascular disease or those at risk of experiencing toxicities related to cancer treatment. It includes recommendations and important management considerations with a focus on 4 main areas: identification of the high-risk population for cardiotoxicity, detection and prevention of cardiotoxicity, treatment of cardiotoxicity, and a multidisciplinary approach to cardio-oncology. All recommendations align with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. Key recommendations for which the panel provides a strong level of evidence include: (1) that routine evaluation of traditional cardiovascular risk factors and optimal treatment of preexisting cardiovascular disease be performed in all patients before, during, and after receiving cancer therapy; (2) that initiation, maintenance, and/or augmentation of antihypertensive therapy be instituted per the Canadian Hypertension Educational Program guidelines for patients with preexisting hypertension or for those who experience hypertension related to cancer therapy; and (3) that investigation and management follow current Canadian Cardiovascular Society heart failure guidelines for cancer patients who develop clinical heart failure or an asymptomatic decline in left ventricular ejection fraction during or after cancer treatment. This guideline provides guidance to clinicians on contemporary best practices for the cardiovascular care of cancer patients.