Breast cancer is the leading cause of morbidity and mortality in women in the developed world and its incidence in the developing world is on the rise. Management of breast cancer requires a multimodality approach and an integration of the services of surgery, radiation, and medical oncology. Radiotherapy after mastectomy or breast conservation leads to reduction in local recurrence by two-thirds. Recent trials and metaanalyses have also demonstrated overall survival benefit with radiotherapy. Of late, however, there has been concern regarding side effects of radiotherapy in breast cancer. Among these the cardiac risk has been particularly been of concern. This review discusses the etiology, manifestations, and evidence in relation to implication of breast cancer radiotherapy in cardiac adverse effects.