Background The transmitral E wave and the peak velocity of early diastolic mitral annular motion (è) both decrease with age, but the mechanisms underlying these age-related changes are incompletely understood. This study investigated the possible contributions of blood pressure (BP) and left ventricular end-diastolic length (LVEDL) to age-related reductions in E and è. Methods The study group were 82 healthy adult subjects <55 years of age who were not obese or hypertensive. Transmitral flow and mitral annular motion were recorded using pulsed-wave Doppler. LVEDL was measured from the mitral annular plane to the apical endocardium. Results Age was positively correlated with diastolic BP and septal wall thickness (SWT), inversely correlated with LVEDL (β = -0.25) after adjustment for sex and body surface area, but was not related to left ventricular end-diastolic diameter (LVEDD). Age was also inversely correlated with E (r = -0.36), septal è(r = -0.53) and lateral è(r = -0.53). On multivariable analysis, E was inversely correlated with diastolic BP and LVEDD, septal èwas inversely correlated with diastolic BP and positively correlated with SWT and LVEDL, after adjusting for body mass index, whilst lateral èwas inversely correlated with diastolic BP and positively correlated with LVEDL. Conclusion The above findings are consistent with higher BP being a contributor to age-related reductions in both E and èand shortening of LVEDL with age being a contributor to the agerelated reduction in è. An implication of these findings is that slowing of myocyte relaxationis unlikely to be the sole, and may not be the main, mechanism underlying age-related decreases in E and è.