there are controversies about the possible benefits of offpump coronary artery bypass grafting (opcabg) compared to on-pump coronary artery bypass grafting (oncabg). for a better perspective on this important issue, we performed a meta-analysis of randomized controlled trials, comparing the two techniques. the objective of this study was to verify which technique applied in coronary artery bypass surgery, opcabg or oncabg, provides better results through a meta-analysis of published randomized trials comparing the two techniques. we carried out a computer-based literature search in pubmed, embase, b-on and science direct from march 2009 to january 2010. the studies covered were recovered according to predetermined criteria. a systematic review of randomized clinical trials was performed in order to evaluate the differences between the two revascularization techniques (opcabg versus oncabg) regarding mortality and morbidity. selected studies did not include patients at high risk and long-term longitudinal evaluations. the meta-analysis focused on nine randomized clinical trials, corresponding to a total of 75,086 patients, and compared opcabg to oncabg. regarding mortality, a reduction of 18% in the risk of cardiovascular mortality (or: 0.82, 95%ci: 0.70 to 0.98, p = 0.03) and 27% in the risk of stroke postoperatively (or: 0.73, 95%ci: 0.63 to 0.85, p = 0.0001) were observed, both in favor of opcabg. concerning the occurrence of complications associated with the procedure, no significant differences were found between the two surgical techniques, particularly with regard to the occurrence of kidney complications (or: 0.97, 95%ci: 0.84-1.14, p = 0, 74) and sepsis (or 0.98, 95%ci: 0.64-1.51, p = 0.93, respectively). off-pump cabg significantly reduces the occurrence of major cardiovascular events (mortality and cva) compared to on-pump cabg surgery.