Aim: To assess left ventricular (LV) diastolic performance by analysis of volume-time curve (VTC) of LV chamber using real-time 3D echocardiography (RT3DE) in comparison with conventional methods with 2D Doppler echocardiography. Methods: Ten subjects with normal LV systolic function (EF: 58 짹 4 %) and 5 patients with global LV dysfunction (EF: 32 짹 13 %) underwent RT3DE. VTCs were generated using 3D computer software (4D LV analysis, TomTec) in all subjects. VTC was sampled at intervals of 1 millisecond. The rate of volume difference (dV/dt) adjusted by LV end diastolic volume (LVEDV) of each patient in percentage {dV*100/LVEDV/dt (%/sec)} was defined as the rate of fractional volume difference (dfV/dt). Two peak dfV/dt during early and late diastole were measured (Figure) and the ratio of early to late dfV/dt was then calculated. Using 2D Doppler echocardiography, E and A velocity of transmitral flow with the ratio (E/A) and E' velocity of the mitral annulus were assessed. Results: The ratio of early to late dfV/dt showed a significant correlation with E/A ratio (r = 0.78, p < 0.05). Peak dfV/dt during early diastole showed a significant correlation with E' velocity (r = 0.76, p < 0.05). However, there was no significant correlation between peak dfV/dt during early diastole and E velocity (r = 0.18, p > 0.05). Conclusion: The rate of fractional volume difference of LV chamber (dfV/dt) during diastole from volume-time curve using RT3DE can be used as an alternative parameter for LV diastolic performance.