We sought to assess the impact of diastolic dysfunction (DD) grade, as per the 2016 American Society of Echocardiography/European Association of Cardiovascular Imaging guidelines, on survival of patients with severe aortic stenosis (AS) who underwent transcatheter aortic valve implantation (TAVI). We included consecutive patients with severe AS who underwent TAVI in our institution. DD grading was determined retrospectively according to the 2016 ASE DD guidelines and categorized to grade I-III and indeterminate grade I-II DD. Comparison of 1-year survival according to DD grade was performed by Kaplan-Meier analysis, and evaluation of DD at 1 year was performed in a subset of patients. Among 606 TAVI patients, 394 (65%) had sufficient data for DD grading. Seventy-seven (20%) had grade I DD, 191 (48%) had grade II, 60 (15%) had grade III, and 66 (17%) had an indeterminate grade between I and II. Baseline characteristics indicate higher rates of atrial fibrillation, brain natriuretic peptide level, pulmonary artery systolic pressure, and indexed left ventricular mass as DD grade increases (all p ≤0.01). In conclusion, comparison of 1-year survival revealed a higher rate of mortality in patients with grade III DD that remained statistically significant following adjustment in a multivariate Cox proportional hazard model. DD grade after TAVI improved in patients with grades II and III. Severe AS patients with grade III DD have higher risk for 1-year mortality after TAVI compared with milder degrees of DD. Further research is warranted to explore a potential benefit for aortic valve therapy at an earlier stage of the disease process.