Radiotherapy to the affected breast or chest wall is well established as an integral part of postoperative management of breast cancer. However, it is known to be associated with increased cardiac and pulmonary morbidities and mortalities. Modern technologies, such as CT planning, have shown to improve treatment planning by accurately delivering optimal doses to the target volumes, while minimizing doses to sensitive structures, thus reducing potential treatment-related adverse effects. The purpose of this study is to report on our experiences with CT planning of adjuvant radiotherapy for breast cancer.