Background: The impact of albuminuria on worsening renal function (WRF) and clinical outcomes after transcatheter aortic valve replacement (TAVR) is unknown. Methods: Overall, 142 patients who underwent TAVR for severe aortic stenosis were divided into two groups based on the preoperative urinary albumin-to-creatinine ratio (ACR): high (ACR >= 30 mg/g) and low (ACR <30 mg/g). The incidence of WRF (an absolute increase in serum creatinine level of >= 0.3 mg/dL or >= 1.5-fold from baseline or dialysis initiation) at 6 months after TAVR and the incidence of all-cause death and heart failure readmission during follow-up were investigated. Results: Half of the examined patients [n=71/142 (50.0%)] had a high ACR. Patients with a high ACR more frequently had WRF at 6 months than those with a low ACR (17.6% vs. 2.9%, p=0.004). Multivariate analysis showed a high ACR was independently associated with WRF (odds ratio, 7.76; 95% confidence interval, 1.62-37.30; p=0.01), whereas baseline estimated glomerular filtration rate <60 mL/min/1.73m(2) was not (odds ratio, 0.34; 95% confidence interval, 0.08-1.50; p=0.15). Patients with a high ACR had a higher risk of composite outcomes of all-cause death and heart failure readmission (p=0.002). Conclusions: Preoperative albuminuria (ACR >= 30 mg/g) was independently associated with WRF at 6 months after TAVR. Furthermore, patients with an ACR >= 30 mg/g had higher risks of all-cause death and heart failure readmission than those with an ACR <30 mg/g. (C) 2021 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.