Since 1995 we have routinely used epiaortic scanning in cardiac surgery and since 1998 we have employed off-pump surgery for coronary revascularization. In patients with extensive atherosclerosis in the ascending aorta we tried to assess whether or not conversion from a planned on-pump to off-pump coronary surgery affects the incidence of postoperative stroke. We studied 28 consecutive patients with extensive atherosclerosis in the ascending aorta undergoing coronary surgery. Extensive atherosclerosis, detected by epiaortic ultrasound, was defined as involvement of 6 or more out of 12 segments. Since 1998 we have converted 15 patients with extensive atherosclerosis in the ascending aorta from on-pump to off-pump. Thirteen patients with similar disease who underwent on-pump before the introduction of off-pump were used as controls. The incidence of stroke in the off-pump group was 0% as compared with 31% in the coronary artery bypass grafting group (P=0.03). Y-grafts were used more often in the off-pump (47%) than in the on-pump group (0%, P<0.01). The non-touch technique of the ascending aorta was also more frequently used in the off-pump group (73 versus 0%, P<0.001). Off-pump reduces the incidence of stroke in patients with aortic atherosclerosis when the disease occupies 50% or more of the ascending aorta.