Objectives: This study aims to compare immediate postoperative outcomes between minimal invasive extracorporeal circulation (MiECC) and conventional extracorporeal circulation (CECC) in adult patients undergoing on-pump coronary artery bypass grafting (CABG). Patients and methods: Between October 2013 and November 2013, a total of 65 adult patients (46 males, 19 females; mean age: 66.1+/-8.6 years; range, 34 to 84 years) who underwent isolated CABG, aortic valve replacement (AVR), or combined AVR with CABG. The patients were stratified by preoperative risk, with higher-risk patients assigned to the MiECC group (n=30) and the remaining patients to the CECC group (n=35). Intra- and postoperative parameters, including cardiopulmonary bypass (CPB) time, aortic cross-clamp time, priming and cardioplegia volumes, 24-h drainage, transfusion requirements, mechanical ventilation duration, intensive care unit (ICU) and hospital stay, and mortality were evaluated. Results: Patients in the MiECC group had higher baseline risk profiles, including older age, chronic obstructive pulmonary disease, and carotid artery stenosis. The MiECC was associated with significantly lower priming (506+/-54 vs. 1150+/-94 mL, p=0.001) and cardioplegia volumes (38+/-7 vs. 939+/-108 mL, p=0.001). Postoperatively, MiECC patients had shorter mechanical ventilation (6.4+/-2.0 vs. 10.2+/-4.9 h, p=0.001), ICU stay (24.5+/-4.2 vs. 45.7+/-6.3 h, p=0.001), and hospital stay (7.3+/-1.2 vs. 10.3+/-2.6 days, p=0.001). Blood product utilization, including red blood cells and fresh frozen plasma, was also significantly lower in the MiECC group, as well. Mortality and major complications were comparable between the groups. Conclusion: Despite higher baseline risk, MiECC provided favorable postoperative outcomes compared to CECC, including reduced transfusion needs, shorter mechanical ventilation, and shorter ICU and hospital stays. The MiECC appears to be a safe and effective strategy even in higher-risk cardiac surgical populations, potentially reducing perioperative morbidity.