Objectives: The purpose of this study was to examine the impact of residual mitral regurgitation (MR) on mortality in patients undergoing transcatheter aortic valve replacement (TAVR). Background: MR is common in patients undergoing TAVR. Data on optimal management of patients with significant MR after TAVR are limited. Methods: The registry consisted of 16 TAVR centers (n = 7,303). Outcomes of patients with ≥ moderate versus lesser grade MR after TAVR were compared. Results: In 1,983 (27.2%) patients, baseline MR grade was ≥ moderate. MR regressed in 874 (44.1%) patients and persisted in 1,109 (55.9%) after TAVR. Four-year mortality was higher for those with MR persistence, but not for those with MR regression after TAVR, compared with nonsignificant baseline MR (43.8% vs. 35.1% vs. 32.4%; hazard ratio [HR]: 1.38; p = 0.008; HR: 1.02; p = 0.383, respectively). New York Heart Association functional class III to IV after TAVR was more common in those with MR persistence vs. regression (14.4% vs. 3.9%; p < 0.001). In a propensity score–matched cohort (91 patients’ pairs), with significant residual MR after TAVR who did or did not undergo staged mitral intervention, staged intervention was associated with a better functional class through 1 year of follow-up (82.4% vs. 33.3% New York Heart Association functional class I or II; p < 0.001), and a numerically lower 4-year mortality, which was not statistically significant (64.6% vs. 37.5%; HR: 1.66; p = 0.097). Conclusions: Risk stratification based on improvement in MR and symptoms after TAVR can identify patients at increased mortality risk after TAVR. These patients may benefit from a staged transcatheter mitral intervention, but this requires further proof from future studies. (Transcatheter Treatment for Combined Aortic and Mitral Valve Disease. The Aortic+Mitral TRAnsCatheter [AMTRAC] Valve Registry [AMTRAC]; NCT04031274).