Objective: The objective of this study is to compare the immediate results of patients undergoing on-pump versus off-pump coronary artery bypass graft (CABG) surgery.Methods: From January 2007 to January 2009, 177 patients underwent CABG. Of these, 92 underwent off-pump CABG and 85 on-pump CABG. We evaluated the demographics, preoperative risk factors, preoperative functional class, and risk assessment by the EuroSCORE. A comparison between both groups regarding the postoperative evolution was carried out as well.Results: The mean number of grafts per patient was 2.48 ± 0.43 in the off-pump group versus 2.90 ± 0.59 in the onpump group. In the off-pump group, 97.8% of patients received an internal thoracic artery graft, while in the onpump group, the percentage was 94.1% (P = 0.03). The rate of complete revascularization was similar in both groups. In the off-pump group, the circumflex artery (circumflex branch of the left coronary artery) was revascularized in 48.9% of the patients versus 68.2% of the patients in the onpump group (P = 0.01). Hospital mortality was 4.3% for offpump CABG and 4.7% for on-pump CABG (P = 0.92). The off-pump group had fewer complications in relation to perioperative myocardial infarction (P = 0.02) and use of intra-aortic balloon pump (P = 0.01).Conclusion: The off-pump CABG is a safe procedure with hospital mortality similar to that observed in on-pump CABG, with lower rates of complications and less need for intra-aortic balloon. Rev Bras Cir Cardiovasc 2012;27(1):38-44 Descriptors