Background: Leptin is a protein product of obesity gene and is syn- thesized mainly by adipose tissue. Objective: The aim of this study was to determine maternal and neo- natal serum leptin levels in preeclamptic and normal pregnancies. Patient and Methods: This corss sectional study was performed on 45 preeclamptic and 45 normotensive pregnant women without other disease.Serum level of leptin was measured in all of pregnant moth- ers and after delivery,measured in umbilical cord of their neonates. This study was performed in Hospitals of Suez Canal University. Results: In this study, when comparing the serum leptin levels be- tween normal pregnancies and pregnancies complicated with both mild and sever preeclampsia there was a highly statistically signif- icant deference in between (p< 0.01). plasmaleptin concentrations were significantly greater in women with pre-eclampsia than in nor- mal controls.Umbilical cord leptin concentrations were significantly greater in women with pre-eclampsia than in normal controls. Cord blood leptin in the present study showed that there is significant pos- itive correlation with severity of pre-eclampsia. Conclusion: According to the results, we detected an increase in ma- ternal plasma and umbilical cord leptin in preeclamticgroup.There was a highly statistically significant deference in between preeclam- tic group and the matched control group