BACKGROUND: The prognostic value of the Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) score in patients undergoing mitral valve transcatheter edge-to-edge repair (M-TEER) remains unclear. This study evaluated the MAGGIC score to predict outcomes after M-TEER in patients with functional (FMR) or degenerative mitral regurgitation (DMR) and compared its performance with conventional surgical and M-TEER-specific risk models. METHODS: We analyzed 3609 patients (FMR, 71%; DMR, 29%) who underwent M-TEER in the OCEAN (Optimized Catheter Valvular Intervention)-Mitral registry. Patients were stratified into MAGGIC score tertiles. The primary outcome was all-cause death at 1 and 3 years. Secondary outcomes included cardiovascular death. Predictive performance was compared with Society of Thoracic Surgeons score, European System for Cardiac Operative Risk Evaluation II, MitraScore, and COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation) score. RESULTS: The median age was 81 years, 55.3% were men, and median MAGGIC score was 30. In the FMR cohort, patients in tertile 3 had higher risks of all-cause death (1 year: adjusted hazard ratio [HRadj], 4.15 [95% CI, 2.34-7.36]; 3 years: HRadj, 1.83 [95% CI, 1.22-2.77]) and cardiovascular death (1 year: HRadj, 2.31 [95% CI, 1.56-3.43]; 3 years: HRadj, 1.61 [95% CI, 1.13-2.31]). In the DMR cohort, tertile 3 was associated with higher all-cause death (1 year: HRadj, 2.84 [95% CI, 1.18-6.86]; 3 years: HRadj, 2.25 [95% CI, 1.07-4.73]) and cardiovascular death at 3 years (HRadj, 3.49 [95% CI, 1.23-9.84]). The MAGGIC score demonstrated comparable or superior discrimination on the basis of the concordance index. CONCLUSIONS: The MAGGIC score independently predicted 1- and 3-year all-cause death after M-TEER in both FMR and DMR cohorts and cardiovascular death in the FMR cohort and at 3 years in the DMR cohort. It demonstrated comparable or superior predictive performance to conventional surgical and M-TEER-specific risk models.