Elevated carbohydrate antigen 125 (CA125) and N-terminal pro-brain natriuretic peptide (NTproBNP) have been associated with adverse outcome after transcatheter aortic valve implantation (TAVI). This study performs a comparison of both biomarkers for prognosis after TAVI. The study includes 363 patients. The primary end point was all-cause death or readmission for worsening congestive heart failure within 1 year after TAVI, and this end point occurred in 16% of the population. The optimal cutoff to predict the primary end point was 18.4 U/ml for CA125 and 2,570 ng/L for NTproBNP. Elevated CA125 levels were present in 52% and were associated with a higher rate of the primary end point (27% vs 3%; p<0.001). In parallel, elevated NTproBNP levels were present in 42% and were also associated with a higher rate of the primary end point (27% vs 8%; p<0.001). After multivariable adjustment, elevated CA125 (hazard ratio [HR] 5.26; p<0.001) and elevated NTproBNP (HR 2.12; p = 0.022) were independent predictors of the primary end point. To explore the utility of combining both biomarkers, CA125 was added to the model containing baseline variables and NTproBNP. Elevated CA125 (HR 4.62; p = 0.001), but not NTproBNP (HR 1.58; p = 0.194), persisted as an independent predictor of the primary end point. Addition of CA125 significantly improved the predictive capability of the model (C-statistic: 0.805 vs 0.776) and the net reclassification index (50%, 95% confidence interval [20 to 84]) with an integrated discriminative improvement of 3.0%. In conclusion, elevated CA125 and NTproBNP predict adverse clinical outcome after TAVI. However, when combining both biomarkers, the predictive capacity of CA125 was superior.