OBJECTIVE: The Cardiothoracic Surgical Trials Network (CTSN) reported that left ventricular reverse remodeling at 2-years did not differ between patients with moderate ischemic mitral regurgitation (MR) randomized to CABG plus mitral-valve (MV) repair (n=150) or CABG alone (n=151). To address health resource use implications, we compared costs and quality-adjusted survival. METHODS: We used individual patient data from the CTSN trial on survival, hospitalizations, quality-of-life, and U.S. hospitalization costs to estimate cumulative costs and quality-adjusted life years (QALYs). A microsimulation model was developed to extrapolate to 10-years. Bootstrap and deterministic sensitivity analyses were performed to address uncertainty. RESULTS: In-hospital costs were $59,745 for CABG plus MV repair vs $51,326 for CABG alone, difference $8,419 (95% uncertainty interval 2,259–18,757). Two-year costs were $81,263 vs $67,341 and QALYs were 1.35 vs 1.30, difference 0.05 (−0.04–0.14), resulting in an incremental cost-effectiveness ratio (ICER) of $308,343/QALY for CABG plus MV repair. At 10-years, its costs remained higher ($107,733 vs $88,583, difference 19,150 [−3,866–56,826]) and QALYs showed no difference (−0.92–0.87), with 5.08 vs 5.08. The likelihood that CABG plus MV repair would be considered cost-effective at 10-years based on a cost-effectiveness threshold of $100k/QALY did not exceed 37%. Only when this procedure reduces the death rate by a relative 5% will the ICER fall below $100k/QALY. CONCLUSIONS: Addition of MV repair to CABG for patients with moderate ischemic MR is unlikely to be cost-effective. Only if late mortality benefits can be demonstrated will it meet commonly used cost-effectiveness criteria.