Radiation-induced heart disease must be considered in any patient with cardiac symptomatology who had prior mediastinal irradiation. Radiation can affect all the structures in the heart, including the pericardium, the myocardium, the valves and the conduction system. In addition to these pathologies, coronary artery disease following mediastinal radiotherapy is the most actual cardiac pathology as it may cause cardiac emergencies requiring interventional cardiological or surgical interventions. Case A 36-year-old man was admitted to the clinic with unstable angina pectoris of one month duration. The patient had no coronary artery disease risk factor. The history of the patient revealed that he had mediastinal radiotherapy due to Hodgkin's disease at 10-year of age. Coronary arteriography showed total occlusion of the left anterior descending artery and 70% stenosis of the proximal right coronary artery. Both arteries are dilated with placement of two stents. Control coronary arteriography at the end of the first year showed patency of both stents and the patient is free of symptoms. Previous radiotherapy to the mediastinum should be considered as a risk factor for the development of premature coronary artery disease. Percutaneous transluminal coronary angioplasty with stent placement or surgical revascularization are the preferred methods of treatment. Preoperative assessment of internal thoracic arteries should be considered prior to surgery. As the radiation therapy is currently the standard treatment for a number of mediastinal malignancies, routine screening of these patients and optimal cardiac prevention during radiotherapy are the only ways to minimize the incidence of radiation-induced heart disease.