Objectives: To evaluate sex differences in in-hospital mortality and 90-day readmission rates among patients undergoing transcatheter mitral valve replacement (TMVR) in the United States of America.Background: Women have higher rates of mortality and rehospitalization than men following many cardiac procedures. TMVR has grown as an alternative to mitral valve surgery for patients at high surgical risk. The rates of TMVR mortality and rehospitalization by sex are unknown. Methods:We analyzed the Nationwide Readmissions Database (NRD) from 2016 to 2019 to identify hospitalizations for TMVR. Sex differences in in-hospital mortality and 90-day readmissions were determined using logistic regression models.Results: Between 2016 and 2019, 4109 hospitalizations for TMVR were identified, comprised of 1758 (42.8%) men and 2351 (57.2%) women. The median age was 74 years for both men and women. There was no significant difference in in-hospital mortality during index hospitalization (6.51% vs. 6.69%; p = 0.852) and all-cause 90-day readmission (28.19% vs. 29.59%; p = 0.563) between men and women.Across the study period, trend analysis did not reveal a significant change in inhospital mortality (men p = 0.087, women p = 0.194) or 90-day readmission rates (men p = 0.569, women p = 0.454). Conclusions:In patients undergoing TMVR, in-hospital mortality and 90-day readmissions are similar between men and women. Between 2016 and 2019, TMVR in-hospital mortality and 90-day readmission rates remained unchanged.Further research is necessary to confirm these findings.