Restenosis is a clinical problem after coronary angioplasty associated with major ischemic events or repeat interventions in 20-50% of the patients undergoing this procedure. Major efforts have been undertaken in the past decade to successfully prevent or treat restenosis but no pharmacologic approach to the problem has as yet been identified to be effective enough in clinical conditions. New strategies to cope with restenosis are targeted by local application of ionizing radiation which markedly reduces cell proliferation after angioplasty in animal experiments. Preliminary clinical trials indicate that endovascular radiation therapy is a safe and effective means to treat restenosis. Randomized, multicenter studies with long follow-up periods are needed to support these early results.