Although intraoperative transoesophageal echocardiography (TOE) has an established role in the management of some cardiac surgical procedures, there is little data on its impact on coronary artery bypass graft (CABG) cases that are stratified for clinical risk. This is a retrospective review of the surgical impact of intraoperative TOE on 2,343 unselected cardiac cases. The surgical impact of TOE findings were rated E (essential)--resulted in changes to the proposed surgical procedure or V (valuable)--the surgical technique for the planned surgery was altered. The surgical impact that routine TOE had on low-, medium- and high-risk CABG cases was also examined. The surgical impact of TOE for the total study population (E + V) was 4.5%. The impact was greatest in combined CABG + mitral valve procedures (18%). The impact in CABG cases was 3.5% overall, with an estimated impact in low-risk patients of 2.8% (95% CI. 2.7-3.0%) versus 6.7% (95% CI. 5.9-7.7%) in high-risk cases. The commonest E-impact in CABG patients was unscheduled valve surgery (2.6% of high-risk patients). The complication rate attributable to TOE was 0.09%. These findings provide indirect evidence for a potential patient benefit from the routine use of TOE in cardiac surgery.