Background and Aim of the Study: Ischemic mitral valve regurgitation (IMR) in patients undergoing coronary artery bypass grafting (CABG) is associated with worse long-term outcomes. The aim of this study was to assess the impact of mitral valve repair with CABG in patients with moderate IMR. Method: This observational study enrolled 3,215 consecutive patients from the Juntendo CABG registry with moderate IMR and multivessel coronary artery disease who underwent CABG between 2002 and 2017. The CABG alone and CABG with mitral valve surgery (MVs) groups were compared. The propensity score was calculated for each patient. Long-term all-cause death, cardiac death, and major adverse cardiac and cerebrovascular events (MACCEs) were compared between the two groups. Results: A total of 101 patients who underwent CABG had moderate IMR in our database. Propensity score matching selected 40 pairs for final analysis. MVs was associated with increased risks of postoperative atrial fibrillation, blood transfusion, and longer hospitalization. There were no differences between the two groups in long-term outcomes, including all-cause mortality, cardiac mortality, and the incidence of MACCEs. Conclusions: Surgical treatment of moderate IMR combined with CABG was as safe as CABG alone, with no differences in long-term outcomes. Further studies are needed to determine the effects of MVs in patients with moderate IMR and severe coronary artery disease.