ObjectiveTo summarize and analyze the clinical outcomes of one-stage transcatheter aortic valve replacement (TAVR) combined with transcatheter mitral valve replacement (TMVR) in patients with concomitant severe aortic and mitral valve disease. Methods We retrospectively collected the clinical data of patients who underwent one-stage TAVR and TMVR at Beijing Anzhen Hospital between January 2019 and May 2025. Baseline characteristics, procedural details, and perioperative echocardiographic results were recorded. Survivors were followed regularly, and the incidence of major adverse cardiovascular and cerebrovascular events was assessed. ResultsA total of 12 high-risk patients with concomitant severe aortic and mitral valve disease were included, comprising 7 males with a mean age of (73.3±5.4) years. Aortic valve pathology included mixed lesions (n=1), aortic regurgitation (n=8), and aortic stenosis (n=3). Among them, 7 patients had previously undergone surgical bioprosthetic aortic valve replacement. Mitral valve pathology consisted of bioprosthetic valve degeneration leading to isolated regurgitation (n=8) or mixed lesions (n=4); 11 patients had a prior surgical bioprosthetic mitral valve replacement. All patients successfully underwent one-stage TAVR combined with TMVR, with 10 procedures performed via the transapical approach, 1 via the transfemoral approach, and 1 via a combined transfemoral-transapical approach. Valve deployment was successful in all cases, with an overall device success rate of 91.7%. The median intensive care unit stay was 1.5 (IQR 1.3, 3.4) d. Early postoperative complications included 2 perioperative deaths and 2 cases of gastrointestinal bleeding, with no other major cardiovascular events observed. During follow-up, there were no deaths, permanent pacemaker implantations, and no occurrences of moderate-to-severe valve stenosis, paravalvular leak, or left ventricular outflow tract obstruction. Conclusion This study demonstrates that one-stage TAVR combined with TMVR is safe and effective in selected high-risk patients with concomitant severe aortic and mitral valve disease, and represents a feasible therapeutic option.