Background: Studies investigating the association between central aortic pressures and diastolic function have been limited. Methods: Consecutive ambulatory patients (n = 281, mean age 49 ± 13 years, 49% male) with normal left ventricular (LV) systolic function were included. The LV filling pressure (E/Em) was estimated by Doppler-derived ratio of mitral inflow velocity (E) to septal (Em) by tissue Doppler, LV relaxation by Em, and central aortic pressures by radial tonometry. Central aortic systolic (cSBP), diastolic (cDBP), mean (cMAP) and pulse pressure (cPP) were entered individually into stepwise linear regression models to determine their association with E/Em or Em. Results: In univariate analysis, cPP correlated most strongly with E/Em (Spearman's ρ = 0.45, P < .001), whereas cSBP correlated most strongly with Em (Spearman's ρ = -0.51, P < .001). Multivariate analysis demonstrated that the pulsatile component of afterload, cPP, contributed most to E/Em (partial r2 = 23%); meanwhile, the nonpulsatile components (cDBP and cMAP) were significant but small contributors (partial r2 of 6% and 5%, respectively) of LV relaxation (Em). Conclusion: The nonpulsatile components of aortic afterload (cMAP and cDBP) exhibited a weak but significant association with LV relaxation, whereas the pulsatile component of afterload, cPP, exhibited strong association with LV filling pressure.