BACKGROUND: Delirium is a cognitive disorder that commonly occurs during hospitalization in acute cardiac care units (ACCU), but its effect after transcatheter aortic valve replacement (TAVR) has not been well evaluated. The objective of this study is to determine the incidence, predictive factors and prognostic impact of delirium following TAVR. METHODS: A total of 501 consecutive patients admitted to an ACCU after TAVR were included. The Confusion Assessment Method was used to evaluate delirium during ACCU stay. Risk factors, preventive pharmacological treatment, peri-procedural characteristics and complications were assessed. Clinical events were recorded with a median follow-up of 24 months. RESULTS: The incidence of delirium after TAVR was 22.0% (n = 110). Previous cognitive impairment (OR 4.17; 95% CI 1.11-15.71; p = 0.035), peripheral arterial disease (OR 4.54; 95% CI 1.79-11.54; p = 0.001), the use of general anaesthesia (OR 2.55; 95% CI 1.32-4.90; p = 0.005), and prolonged mechanical ventilation (OR 18.86; 95% CI 1.85-192.58; p = 0.013) were significantly associated with the development of delirium. Patients with delirium had a greater hospital length of stay (7.5 [5.5-13.5] vs 5.6 [4.6-8.2] days, mean difference - 3.49; 95% CI -5.45 to -1.52; p < 0.001), and higher in-hospital (OR 2.68; 95% CI 1.02-6.99; p = 0.045), 1-year (HR 2.09; 95% CI 1.13-3.87; p = 0.018) and 2-year mortality (HR 1.94; 95% CI 1.12-3.34; p = 0.017). CONCLUSIONS: Delirium is a frequent complication in patients admitted to ACCU after TAVR, and is associated with prolonged hospital stay and higher in-hospital and mid-term mortality.