Treatment of in-stent restenosis after implantation of a drug-eluting stent is a critical issue. We provide the first report of the use of intravascular radiation therapy for this purpose in a 73-year-old diabetic patient stented for small-vessel bifurcation; treatment of Cypher diffuse in-stent restenosis with (32)P brachytherapy proved successful at clinical and angiographic follow-up at 7 months. This finding should encourage systematic studies on the safety and efficacy of IRT in this problematic setting.