Copyright © 2017 by Türkiye Klinikleri.Objective: This study was performed to compare the obstetric outcomes between preeclampsia and superimposed preeclampsia cases. Material and Methods: This retrospective study included 500 women with preeclampsia and 101 women with superimposed preeclampsia who delivered in a tertiary care center. Clinical findings, maternal and perinatal outcomes were compared between the two groups. Results: In cases of preeclampsia, antenatal, perinatal, neonatal mortality rates were 13.4%, 17.9%, 5.1% respectively. The rate of cases which mother's life at risk was 30.2%. The antenatal, perinatal and neonatal mortality rates were 12.9%, 19.8%, and 8.9%, respectively, in cases of superimposed preeclampsia and the rate of cases where mother's life was at risk was 25.7%. There was no significant difference between the two groups in terms of time of onset of the symptoms (p = 0.669), mean birth week (p = 0.410) and birth weight (p= 0.340). Rates of intrauterine growth retardation (p = 0.434), early and late neonatal loss (p = 0.111, p = 0.848) and stillbirth (p = 0.887) did not differ between the groups. Although maternal deaths and maternal near miss cases were not significantly different between the two groups (p=0.370), the rate of complication with eclampsia in preeclampsia cases was higher than that of superimposed preeclampsia cases (p=0.001). Conclusions: Preeclampsia and superimposed preeclampsia have similar obstetric outcomes. Further research is needed to elucidate the mechanisms underlying eclampsia in preeclampsia cases.