Endothelial dysfunction plays an important role in the pathogenesis of preeclampsia. Increased number of circulating endothelial cells (CECs) have previously been reported after various diseases associated endothelial injury. The aim of this study was to evaluate the CECs in patients with preeclampsia and to demonstrate any association between CECs and homocysteine, which is another marker of vascular injury. The study included 20 preeclamptic, 15 hypertensive women, 15 healthy pregnant and 15 healthy non-pregnant women. All subjects had normal renal function. Systolic and diastolic blood pressures, serum homocysteine levels were measured. To isolate CECs, peripheral blood was first incubated with anti-CD-146 antibody and subsequently conjugated to immunomagnetic beads. Cells were stained with acridine and counted. Preeclamptic patients had elevated numbers of CECs (13.275.2 cells/ml) compared with hypertensive patients (6.970.8 cells/ml), healthy pregnants (5.271.4 cells/ml) and non-pregnant controls (4.071.8 cells/ml), (Po0.0001). Serum homocysteine level in preeclamptic patients (9.572.8 lmol/l) was significantly higher compared with healthy pregnants (6.070.6 lmol/l), was not different from hypertensive patients (11.572.3 lmol/l, P40.05), but it was lesser compared with non-pregnant controls (12.273.3 lmol/l, Po0.0001). Also, significant correlation between CECs and systolic blood pressure (Po0.0001, r ¼ 0.63), diastolic blood pressure (Po0.0001, r ¼ 0.64) and serum homocysteine (Po0.01, r ¼ 0.55) levels were found in preeclamptic patients. CECs as a marker of endothelial injury were significantly higher in patients with preeclampsia than in hypertensive patients, healthy pregnants and normal controls. Further studies are needed for the prognostic and potential importance of CECs in preeclampsia.