Background The prevalence of concomitant significant mitral regurgitation (MR) in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR) ranges from 2% to 33%. The impact of significant MR on post-TAVR outcomes remains controversial. Methods The data from a cohort of patients with symptomatic severe AS undergoing TAVR at out institution were retrospectively analyzed. The last transthoracic echocardiogram (TTE) before the index TAVR procedure was selected as the baseline assessment of the degree of MR. The total study cohort (N = 589) was divided into 2 groups: significant ≥moderate MR (n = 68) versus nonsignificant <moderate MR (n = 521) at baseline. The 2 groups were compared in regard to baseline, imaging, procedural, and postprocedural characteristics. In-hospital, 30-day, and 1-year outcomes were assessed. Multivariate Cox regression survival analyses were performed to test the independent effect of ≥moderate MR on mortality at short- and long-term follow-up periods. Results Patients with ≥moderate MR had a higher mortality rate versus patients with <moderate MR during the initial 30-day follow-up after TAVR (unadjusted log-rank P =.011, risk-adjusted P =.031, hazard ratio = 2.40, 95% CI 1.08-5.29). However, the mortality rates at 1-year follow-up postprocedure were similar between the 2 groups (unadjusted log-rank P =.553, risk-adjusted P =.331, hazard ratio = 0.70, 95% CI 0.35-1.43). Among the original ≥moderate group, 62.5% and 77.7% of patients had improved to <moderate MR at 30-day and 1-year follow-up, respectively. Conclusions Moderate or greater MR in patients undergoing TAVR is associated with a higher 30-day but not 1-year mortality. A majority of the patients demonstrated significant improvement in MR following TAVR.