OBJECTIVE To assess cardiac function by means of the modified myocardial performance index (Mod-MPI) in fetuses of pre-eclamptic mothers without intrauterine growth restriction and to compare this with values from normal controls. METHODS A cross-sectional study was conducted including a total of 72 fetuses at between 26 and 40 weeks' gestation. Forty fetuses of healthy mothers were assigned as the control group (Group I) while 15 fetuses of mildly pre-eclamptic mothers constituted Group II and 17 fetuses of severely pre-eclamptic mothers constituted Group III. Two-dimensional gray-scale and Doppler fetal echocardiography was used to exclude cardiac anomalies and calculate the Mod-MPI. RESULTS The mean+/-SD Mod-MPI values of Groups I, II and III were 0.43+/-0.045, 0.44+/-0.064 and 0.44+/-0.064, respectively (P=0.680). The mean aortic peak systolic velocity (PSV), the mean mitral valve early ventricular filling (E-wave) and active atrial filling (A-wave) peak velocities were significantly lower in fetuses of severely pre-eclamptic mothers than in fetuses of mildly pre-eclamptic mothers and control fetuses. CONCLUSION The fetal global myocardial function assessed by Mod-MPI does not seem to change in mild or severe pre-eclampsia. The lower mitral E-wave and A-wave peak velocities and the lower aortic PSV seem to reflect the increased cardiac afterload against which the fetal heart has to work, rather than systolic or diastolic cardiac dysfunction, in the fetuses of severely pre-eclamptic mothers.