Among patients undergoing transcatheter aortic valve replacement (TAVR), prognosis is impacted by nutritional status, but the influence of the nutritional risk index (NRI) is unknown. Here we calculated the NRI to determine the prevalence and prognostic impact in terms of mortality of malnutrition in TAVR patients. This retrospective multicenter study included 941 patients who underwent TAVR between 2008 and 2016 (mean age, 80.7 ± 6.5 years; 57% female). The NRI was calculated as 1.519 × albumin (g/L) + 41.7 × (real weight kg / ideal weight kg). The mean NRI was 98.1 ± 7.0%. The patients were stratified into the following groups based on malnutrition risk: severe (NRI < 83.5; n = 83; 8.82%), moderate (83.5 ≥ NRI < 97.5; n = 370; 39.32%), mild (97.5 ≥ NRI < 100; n = 102; 10.84%), and no risk (NRI ≥ 100; n = 386; 41.02%). During the follow-up period (2.1 ± 1.1 years), 186 patients died, representing 19.8% of the total cohort. Cox regression models were used to analyze the relationship between NRI and mortality during follow-up. Compared to patients with no or mild nutritional risk, those with moderate or severe nutritional risk had a 45% greater risk of mortality during follow-up (adjusted HR, 1.45; 95% CI, 1.05–1.99; P = 0.021). Malnutrition is common among TAVR patients. Our present data indicated that the NRI was independently associated with increased risk of death during long-term follow-up after TAVR. Based on its potential to improve risk prediction, NRI appears to be a promising tool for the clinical assessment of patients who are candidates for TAVR. •Malnutrition, assessed by the NRI, is common among TAVR patients.•NRI was independently associated with mortality during long-term follow-up after TAVR.•NRI as a tool for detection of malnutrition should be included in the evaluation process of TAVR patients.