OBJECTIVE: To investigate the use of a cutting balloon to overcome aorto-ostial lesions before stent implantation and thereby reduce the restenosis rate. DESIGN: Observational follow up study. SETTING: Tertiary referral centre. PATIENTS: Eight patients (two female, six male) aged 58.2 (SD 10.1) years with Canadian Cardiovascular Society (CCS) grade II-IV angina were recruited. They each had a single target lesion (three in native coronaries, five in vein grafts). INTERVENTION AND RESULTS: After high pressure angioplasty (18 (3.8) bar), there was only a small reduction in the luminal stenosis, from 82 (9)% to 68 (10)%, as assessed by on line quantitative coronary angiography. However, using the cutting balloon there was a marked reduction in the luminal stenosis to 44 (15)%, facilitating stent insertion. Subsequent high pressure dilatation resulted in a final stenosis of 10 (7)%. At 6 (2) months' follow up the marked symptomatic improvement, to CCS angina grade 0-II, was maintained and there were no further cardiac events or interventions. CONCLUSION: Cutting balloon angioplasty followed by stent insertion is a feasible technique for the treatment of aorto-ostial lesions, meriting further investigation.