The objective of this study was to evaluate the prognostic value of the myocardial performance index (MPI), assessed by color-coded tissue Doppler imaging (TDI) M-mode through the anterior mitral leaflet. Color TDI M-mode through the mitral leaflet is an easy, very fast, and precise method to estimate cardiac intervals and thus obtain the MPI, but the diagnostic and prognostic values of this parameter are unknown. In a large population study, cardiac function was evaluated in 1,100 participants by conventional echocardiography and TDI. MPI was calculated from pulse-wave Doppler analyses of left ventricular in- and outflow using standard procedures (MPI(conv)) and by color-coded TDI M-mode through the mitral leaflet in the apical 4-chamber view (MPI(TDI)). MPI(TDI) was increased in subjects with coronary heart disease (CHD) compared to controls, even after multivariable adjustment (p <0.002). During follow-up (median 5.3 years), 90 participants died. MPI(TDI) was significantly associated with overall mortality, and risk of dying increased by 31% per 0.1 increase in MPI(TDI). In contrast to MPI(conv), MPI(TDI) provided independent prognostic information in a multivariable Cox proportional hazard model (adjusting for age, gender, body mass index, heart rate, mean arterial blood pressure, and CHD), with a hazard ratio of 1.18 (p = 0.01) per 0.1 increase in MPI(TDI). In conclusion, MPI(TDI) is a quick, simple, and reproducible measurement, which is increased in subjects with CHD and provides independent prognostic information in a low-risk population