Objective: To investigate the short- and medium-term effects of combined mitral valve surgery (MVS) and coronary artery bypass grafting (CABG) versus CABG alone for patients with moderate ischemic mitral regurgitation (IMR). Design: Meta-analysis of 4 randomized controlled trials (RCTs) and 5 observational studies. Setting: Hospitals that perform cardiac surgery. Participants: The study included 1,256 cardiac surgery patients from 4 RCTs and 5 observational studies. Interventions: None. Measurements and Main Results: Four RCTs and 5 observational studies were included in this meta-analysis. Concomitant MVS significantly reduced the residual rate of postoperative IMR (moderate or severe) (RCTs: OR -0.32, 95% confidence interval [CI] -0.58 to -0.07, p = 0.01; observational studies: OR -0.23, 95% CI -0.34 to -0.12, p < 0.0001) and the proportion of surviving patients with New York Heart Association class III or IV (RCTs: OR 0.45, 95% CI 0.31-1.8, p = 0.008), but did not improve early mortality (RCTs: OR 0.91, 95% CI 0.30-2.74, p = 0.87; observational studies: OR 1.63, 95% CI 0.88-3.05, p = 0.12) or medium-term mortality (RCTs: OR 0.89, 95% CI 0.46-1.74, p = 0.73; observational studies: OR 0.94, 95% CI 0.65-1.37, p = 0.48) compared with CABG alone. Moreover, adding the mitral valve procedure did not significantly increase the risk of stroke (RCTs: OR 2.27, 95% CI 0.73-7.08, p = 0.16; observational studies: OR 0.55, 95% CI 0.10-3.06, p = 0.50). Conclusions: The potential benefits of combined MVS and CABG could outweigh its risks for patients with moderate IMR. (C) 2016 Elsevier Inc. All rights reserved.