Objectives Prehypertension, which may be the precursor of hypertension, is an important public health problem in the community. Myocardial performance index (MPI) is a noninvasive Doppler measurement of global ventricular function. Thus, our aim was to evaluate left ventricule (LV) functions with the MPI in prehypertensive patients with normal coronary artery angiography. Patients and materials Forty prehypertensive patients (21 women and 19 men), with blood pressures between 120/80 and 139/89 mmHg, and 40 normotensive controls (18 women and 22 men), with blood pressures under 120/80 mmHg, were included in the study. Patient population comprised those who underwent coronary angiography because of typical angina and had normal coronary arteries. The MPI was calculated and compared between the two groups. Results No statistically significant differences were found between the two groups in terms of age, sex, or other demographic characteristics (P >0.05). Moreover, LV ejection fraction, late diastolic flow, deceleration time, isovolumetric contraction time, and ejection time values were not significantly different between the two groups (P >0.05). However, early diastolic mitral inflow velocity, E/A ratio, isovolumetric relaxation, and MPI were all significantly higher in the patient group than in the control group. Conclusion The MPI was increased in prehypertensive patients. This result demonstrates that LV diastolic and systolic functions may be negatively affected in patients with prehypertension. The advantages of our method are as follows: it is simple, it does not demand special equipment, and it is not time consuming. Copyright (C) 2017 Wolters Kluwer Health, Inc. All rights reserved.