The hemodynamic performance of self-expandable valves (SEV) is a preferable choice for small aortic annuli in transcatheter aortic valve replacement (TAVR). However, no data are so far available regarding the relationship between the size of SEV and clinical outcomes. This study sought to evaluate the impact of prosthesis size on adverse events after TAVR using SEV. We retrospectively analyzed 1400 patients (23mm SEV: 13.6%) who underwent TAVR using SEV at 12 centers. The impact of SEV size on all-cause death and heart failure (HF) after TAVR was evaluated by multivariate Cox regression and propensity score (PS) matching analysis. During the follow-up period (median 511 days), 201 all-cause deaths and 87 HF rehospitalizations were observed. The incidence of all-cause death was comparable between small (23mm SEV) and larger-size (26 or 29mm SEV) (16.8% vs. 13.9%, log-rank P = 0.29). The size of SEV was not associated with higher incidence of all-cause death (hazard ratio [HR] 1.21, 95% confidence interval [CI] 0.79 to 1.86 in Cox regression; HR 1.31, 95% CI 0.77 to 2.23 in PS matching) and HF after TAVR (subdistribution-HR 0.79, 95% CI 0.37 to 1.72 in Cox regression; subdistribution-HR 1.00, 95% CI 0.44 to 2.30 in PS matching). The multivariate model including post-procedural prosthesis-patient mismatch showed consistent results. In conclusion, small SEVs had comparable mid-term clinical outcomes as compared to larger-size SEVs, even if the prosthesis-patient mismatch was observed after TAVR.