BACKGROUND: Severe aortic regurgitation (AR) and mitral regurgitation (MR) can lead to left ventricular (LV) systolic dysfunction; however, there are limited data about recovery of LV after surgery for AR or MR. Little is known to guide the management of combined AR and MR (mixed valvular heart disease [VHD]). This study is sought to investigate the predictors of postoperative LV function recovery in left-sided regurgitant VHD with reduced left ventricular ejection fraction (LVEF), especially for mixed VHD. METHODS: From 2010 to 2020, 2053 adult patients underwent aortic or mitral valve surgery at our center. The patients with valvular stenosis, infective endocarditis, concomitant revascularization, and preoperative LVEF ≥40 % were excluded. A total of 127 patients were included in this study: 22 patients with predominant AR (AR group), 64 with predominant MR (MR group), and 41 with combined AR and MR (AMR group). RESULTS: The mean preoperative LVEF was 32.4 %, 30.7 %, and 30.2 % (p = 0.44) in the AR, MR, and AMR groups, respectively. The AR group was more likely to have postoperative LVEF recovery. The cut-point of left ventricular end-systolic diameter (LVESD) for better recovery was 49 mm for the MR group and 58 mm for the AMR group. CONCLUSION: LV dysfunction due to combined AR and MR has similar remodeling reserve as AR, and better recoverability than MR. Thus, double-valve surgery is recommended before the LVESD is > 58 mm.