Recently, myocardial performance index (MPI) which measured by TDI is a novel method for accurately evaluating systolic and diastolic ventricular function. The index of combined systolic and diastolic ventricular myocardial performance was proposed as a potentially useful predictor of global cardiac function. The aim of this study was to assess myocardial performance index by tissue Doppler imaging in highly competitive athletes and patients with left ventricular hypertrophy due to systemic hypertension in order to determine whether this variable might be used to define these groups. We compared 56 subjects with different types of left ventricular hypertrophy 14 patients with systemic hypertension, and 14 athletes with 28 normal subjects. The peak velocities of myocardial motion at inferior site of mitral annulus were measured by tissue Doppler echocardiography. Although hypertensive patients with left ventricular hypertrophy had lower systolic and diastolic velocities that those of athletes, mean MPI was higher in patients and controls than those of athletes (0.74+/-0.02, 0.46+/-0.01, and 0.27+/-0.02, respectively, p<0.001). MPI measured by TDI may facilitate to differentiate between pathologic and physiologic hypertrophy.