Over a 3-year period 17 patients underwent a total of 25 coronary artery bypass grafts utilising bovine internal mammary artery [BIOFLOW]. Three patients died in the peri-operative or early post-operative period allowing detailed information to be gathered on 14 patients. Seven patients who had had a total of 11 Bioflow grafts implanted underwent post-operative coronary angiography at a mean time of 19 months after surgery revealing occlusion in all the Bioflow grafts. Two patients who underwent aortic valve replacement combined with single Bioflow grafts were symptom-free and refused re-study. Two patients who had three coronary grafts each, including single Bioflow grafts, refused re-study though one of them had recurrent anginal symptoms. Two patients, one with recurrent anginal symptoms, who had a total of four Bioflow grafts were considered unfit for restudy on medical (non-cardiac) grounds. One patient with two Bioflow grafts and recurrent symptoms refused long-term follow-up. Despite reports of good early patency rates with the Bioflow graft, we have not found this to be the case even when patients were anticoagulated post-operatively. We do not recommend the use of this graft as early occlusion is to be expected, which may result in an early return of anginal symptoms.