In year 2016, the American Society of Echocardiography (ASE) and the European Association of Cardiovascular Imaging (EACVI) updated Recommendations for the assessment and grading of diastolic dysfunction (DD). We aimed to assess the applicability of this DD grading method and its association with prognosis in patients with severe aortic stenosis (AS) who underwent transcatheter aortic valve implantation (TAVI). We retrospectively identified 237 consecutive patients with severe AS who underwent trans-femoral TAVI. Baseline transthoracic echocardiography was evaluated to assess pre- and post-TAVI diastolic function according to the current ASE/EACVI Recommendations. Prior to TAVI, 41 (17%) patients were diagnosed as having grade I DD, 111 (47%) patients had grade II DD, 80 (34%) had grade III DD. DD grade after TAVI decreased (p < 0.001) with 75 patients (32%) reclassified to a lower DD grade. During the median follow-up of 1,320 days, 136 (57%) patients died. In univariable Cox proportional hazards model analysis, neither pre- nor post-TAVI DD grade were associated with prognosis. However, patients with grade III DD detected before TAVI and AR≥ 2 after TAVI had poorer survival (p<0.008). Patients with grade III DD detected after TAVI and AR≥ 2 after TAVI had poorer prognosis (p = 0.002). TAVI improves DD grade. While poor DD grade was not associated with mortality after treatment of AS by TAVI, concomitant presence of DD and post-procedural AR carried a poor prognosis.