Background: Heart failure with normal ejection fraction (HFNEF) suggests that the physiological abnormalities are not restricted to diastole only, and that systolic function is not entirely preserved. However, Myocardial performance index (MPI) derived by tissue Doppler imaging (TDI) has an advantage of recording systolic and diastolic velocity simultaneously on the same cardiac cycle. Objective: The aim of this study is to determine whether TDI-MPI is a reliable index in assessing HFNEF by comparing with conventional echocardiographic parameters. Methods: Consecutive 204 patients (mean age; 64.7짹12.9 years, 87 males) were allocated to diastolic dysfunction (DD) or HFNEF groups (N=103 and 101, respectively). TDI-velocity and its MPI were measured near the mitral septal annulus with appropriate filter and gain settings. Results: MPI value was greater in the HFNEF compared with the DD group (0.75짹0.28 vs. 0.44짹0.13, p≺0.001). The area under the receiver operating characteristic curve of MPI for the detection of HFNEF consistent with high NT-ProBNP level was 0.90 (95% CI; 0.85 ~ 0.94, p≺0.001), and 0.49 of MPI was determined to be the optimal cut-off value (sensitivity 92.1%, specificity 74.8%). Conclusion: MPI derived by TDI may be feasible and clinically helpful for the evaluation of DD and HFNEF.