Atherosclerotic coronary artery disease is not uncommon in elderly patients with hypertrophic cardiomyopathy. These disease entities are increasingly being treated with catheter-based techniques. We report an elderly symptomatic woman treated simultaneously with coronary angioplasty, stenting and transcoronary ablation of septal hypertrophy who developed in-stent restenosis 7 months later, and was then treated with brachytherapy. Six-month and 1-year post-brachytherapy follow-up revealed a good angiographic result and adequate symptomatic relief. This is the first report describing the feasibility and efficacy of intracoronary beta radiation in a patient with hypertrophic cardiomyopathy.