Objective: In a retrospective study, we compared two groups of consecutive patients operated by the same team during the year 2000 for coronary artery disease with the use of extracorporeal circulation (group 1, n = 230) or on the beating heart using the Octopus 11 plus stabiliser (group 2, n = 228). High-risk patients were identified by a EuroSCORE plus 6. EuroSCORE definitions and predicted risk models were utilized to compare the variables of the groups. Methods: There were no significant differences between the preoperative variables of the groups in age, gender, left ventricular function, diabetes and peripheral vascular and renal disease as is indicated by the Euroscore (resp. 4.7/5.1 p = 0.107). Calcification of the ascending aorta and chronic obstructive lung disease were statistically significant more prevalent in the beating heart group. No differences in preoperative variables in the high-risk patients group (Euroscore 8.5/8.1 p = 0.356) except for calcification of the ascending aorta. Results: All patients underwent a full revascularisation through a midline sternotomy. Significant more distal anastomoses were performed in group 1 (3.7 per patient (1-6)) with regard to group 2 (2.9 per patient (1-6)). Anesthesia, postoperative treatment and follow up were equal for both groups. A significant lower incidence of atrial fibrillation (p = 0.010), shorter ICU stay (p = 0.031) and renal insufficiency (p = 0.033) was reported in group 2. In the low risk group, we could not diagnose any difference between the two groups, except for atrial fibrillation. The benefits of the beating heart surgery however were more pronounced in the high-risk patent as is indicated by a significant reduction of the ICU stay by 1 day (3.5d/2.5d (p = 0.028)), better preservation of the renal function (p = 0.017) and a significant reduction of the length of hospital stay by more than two days (p = 0.040). A lower incidence of atrial fibrillation, however not significant. Conclusion: In our experience, beating heart surgery is a safe alternative for conventional coronary. heart surgery. High-risk patients do benefit most from this technique. It became our first choice in the elderly patient and patients presenting with higher co-morbidities. (C) 2003 The International Society for Cardiovascular Surgery. Published by Elsevier Science Ltd. All rights reserved.