A 62-year-old man underwent radiotherapy to the left upper chest for treatment of Pancoast syndrome on a background of previous coronary artery bypass grafting 12 years earlier. Within 1 year, he developed significant stenoses of both the left internal mammary artery (LIMA) graft and ostial left vertebral artery, presumably related to therapeutic radiation exposure. Initially diagnosed using computed tomography coronary angiography, the patient underwent percutaneous coronary intervention and insertion of a drug-eluting stent (DES) to the ostium of the LIMA graft via a left radial approach. He remains clinically well at 6-month follow-up. This is the first reported case in the literature of DES treatment of a radiation-induced vascular stenosis; however, the incidence of cardiovascular disease is elevated in such cases. In patients with a prior history of mantle radiation, consideration should be given to the routine assessment of internal mammary conduits prior to coronary artery bypass surgery. (Circ J 2008; 72: 1904 - 1906)