Background: Lower systolic blood pressure (SBP) after transcatheter aortic valve replacement (TAVR) has been associated with increased mortality, but the role of diastolic blood pressure (DBP) has not been carefully examined. Methods: Among patients enrolled in the Medtronic intermediate, high, and extreme risk TAVR trials, we included those with a transcatheter (n=1794) or surgical (n=1103) valve implanted who were alive at 30 days. Early post-AVR SBP and DBP (average of discharge and 30-day measurements) were evaluated as continuous and categorical variables and associations with 30-day to 1-year mortality, aortic valve-related hospitalization, stroke, and myocardial infarction (MI) evaluated. Those with SBP <90 or >180 were excluded. Results: Among 2897 patients, after adjustment, restricted cubic spline curves demonstrated an association between lower DBP (below 60 mmHg, which represented 30% of patients) and increased all-cause and cardiovascular mortality and repeat hospitalization. These relationships were unchanged when patients with moderate to severe aortic regurgitation post-AVR were excluded. Higher DBP values (60-100 mmHg) were not associated with these outcomes. There was no significant association between DBP and stroke or MI at any level of DBP. After adjustment, compared to DBP 60 to <80, DBP 30 to <60 was associated with increased all-cause (adjusted HR 1.62, 95% CI 1.23-2.14) and CV mortality (adjusted HR 2.13, 95% CI 1.52-3.00) and repeat hospitalization (adjusted HR 1.58, 95% CI 1.17-2.15), but DBP 80 to <100 was not. The association between lower DBP and increased all-cause mortality was consistent across multiple subgroups. Lower SBP (below ~115-120 mmHg) was also associated with increased mortality in adjusted models, but when SBP and DBP were both included in models, DBP retained a significant association with mortality whereas SBP did not. Conclusion: Lower BP, particularly lower DBP, in the first month after transcatheter or surgical AVR is common and is associated with increased mortality and other poor clinical outcomes. Further studies are needed to understand this relationship and determine its implications for BP management after AVR.