The purpose of this study to evaluate the cffDNA level in maternal venous samples obtained from pre-eclamptic pregnant women and whether it shows a correlation with uteroplacental blood flow or not.One hundred and twenty pregnant women during third trimester who attended Cairo university hospital (El Kasr El Aini) participated in this cross sectional study between January (2011) – January (2012). Maternal venous samples were obtained from them for cffDNA extraction. Sixty samples were obtained as control from normotensive pregnant women and sixty from pre-eclamptic women. Doppler U/S including umbilical artery RI, uterine artery RI, PI and MCA / Umb PI ratio was done to these pregnant women.