Aim: Quantitative changes of cell-free fetal DNA in maternal plasma as an indicator for impending preeclampsia was reported in different studies. Cell-free fetal nucleic acids can be detected in maternal circulation during pregnancy. Our aim was to determine the higher rate of fetal DNA levels in maternal blood in pre-eclampsia compared to normal pregnancies and the clinical use of real-time polymerase chain reaction (PCR) in the Turkish population as a marker. Material and Methods: According to their gestational ages, the plasma levels of 30 pre-eclamptic women at 26-40 weeks of pregnancy were matched with 18 healthy pregnant women. Cell-free fetal DNA levels in maternal plasma were compared using real-time PCR technology. For the quantitative measurement of fetal DNA from maternal blood, the relative quantification PCR process was applied to all samples, using SRY and GAPDH genes. These patients were classified as pre-eclamptic and control groups and were matched according to weeks of pregnancy. Results: Free fetal DNA levels of 30 pre-eclamptic patients were compared to healthy pregnant women and an average 3.06-fold increase was observed. During the second trimester, free fetal DNA levels were 1.5 times higher in pre-eclamptic patients. This increase was 3.5-fold during the third trimester. The DNA increase of pre-eclamptic patients was 4.1-fold and 3.4-fold during 29th-33rd and 34th-40th weeks, respectively. Conclusions: Cell-free fetal DNA in maternal blood could be used as a marker for identifying subjects at increased risk of developing pre-eclampsia. © 2012 The Authors.