Objectives This study sought to assess the influence of chronic kidney disease (CKD) classification on clinical outcomes in patients undergoing transcatheter aortic valve implantation (TAVI). Background The prognostic value of impaired renal function according to CKD classification has not been thoroughly investigated in very elderly TAVI cohorts. Methods Data from 642 consecutive patients who underwent TAVI were prospectively collected. Clinical outcomes were compared in enrolled patients, divided into CKD stage 1+2, CKD stage 3a, CKD stage 3b, and CKD stage 4 on the basis of estimated glomerular filtration rate ≥60, 45 to 59, 30 to 44, and 15 to 29 ml/min/1.73 m2 , respectively. Results Among the study patients (mean age: 83.5 ± 6.5 years, logistic European System for Cardiac Operative Risk Evaluation score 20.0% range: 13.6% to 28.8%), 34% were categorized as CKD stage 1+2 (n = 218), 28.3% as CKD stage 3a (n = 182), 28.2% as CKD stage 3b (n = 181), and 9.5% as CKD stage 4 (n = 61). Thirty-day and cumulative 1-year mortality rates increased significantly across the 4 groups (6.9% vs. 8.8% vs. 13.3% vs. 26.2%, p = 0.002, and 17.2% vs. 23.4% vs. 29.2% vs. 47.8%, p < 0.001, respectively). After adjustment for considerable influential confounders in a Cox multivariate regression model, CKD stage 4 was associated with increased risk for 30-day mortality (hazard ratio: 3.04; 95% confidence interval CI: 1.43 to 6.49; p = 0.004), and CKD stages 3b and 4 were related to increased cumulative 1-year mortality (hazard ratios: 1.71 and 2.91; 95% CI: 1.09 to 2.68 and 1.73 to 4.90; p = 0.020 and p < 0.001, respectively) compared with CKD stage 1+2 as the referent. Conclusions Classification of CKD stages before TAVI allows risk stratification for early and midterm clinical outcomes. TAVI for patients with CKD stage 4 is still considered challenging because of high mortality rates after the procedure.