The aim of this study was to determine whether clinical characteristics have an influence on left (LV) and right ventricular (RV) diastolic function indices measured by echocardiography in healthy individuals. Five hundred and three volunteers (253 women and 250 men) aged 18-66 years (mean 36.9 +/- 11.9) who were normotensive and free of clinically apparent heart disease were included in the study. Mitral and tricuspid peak E wave and A wave velocities, EIA ratio, deceleration time (DT) of the E wave, and left ventricular isovolumetric relaxation time (IVRT) were evaluated as left and right ventricular diastolic function indices. In order to determine the effects of age, gender, body surface area (BSA), waist/hip ratio (WHR), and heart rate (HR) on left and right ventricular diastolic function indices Student's t test and correlation and linear regression analysis were used. IVRT and deceleration time of the mitral E wave (DTm) were significantly longer in men. Mitral and tricuspid A wave velocities, tricuspid EIA ratio, and deceleration time of the tricuspid E wave (DTt) were similar in both genders. Mitral and tricuspid E wave velocities and mitral E/A ratio were greater in women. Mitral E wave velocity and IVRT mostly correlated with WHR. Age was found to be the most important factor affecting mitral A wave velocity, DTm, E/A ratio, and right ventricular diastolic function indices, This study shows that age, heart rate, body surface area, and waist/hip ratio have important correlations with Doppler echocardiographic diastolic indices in normal individuals and should be considered in the evaluation of LV and RV diastolic function.