Pre-eclampsia complicates approximately 6-8% of all pregnancies. Epidemiologic studies have demonstrated a relationship between pre-eclampsia and cardiac morbidity and mortality later in life, but the effect of pre-eclampsia on electrical cardiac activity during the acute phase has not yet been understood. The aim of this study was to investigate ECG alterations during pre-eclampsia. Prepartum ECGs of 76 consecutive pre-eclamptic women were compared with those of 76 healthy pregnant women. All of the routine ECG parameters were considered, and ventricular repolarization was assessed by QT interval and QT dispersion (QTd). Pregnancies complicated by pre-eclampsia showed a significant alteration of ventricular repolarization compared with the control group. Among ECG parameters, QT and QTc intervals and QTd were more prolonged in pre-eclamptic women. Multivariate analysis also showed that pre-eclampsia was the only independent determinant of QTd. In conclusion, pre-eclampsia has a significant effect on ventricular repolarization. This alteration could, in part, explain the increased cardiovascular risk of women with a history of pre-eclampsia. Further studies are necessary to confirm the relationship between ventricular repolarization abnormalities and increased cardiovascular risk later in life.