Objective: The purpose of this study was to investigate maternal plasma soluble vascular cytoplasmic adhesion molecule-1 (sVCAM- 1) and fibronectin levels in the patients with early-onset preeclampsia (EOP) and late-onset preeclampsia (LOP) and also to determine whether different mechanisms are involved in these two forms of disorders. Material and Methods: The authors performed a case control study consisting of randomly selected 80 healthy pregnant women (group 1= control group) and 80 preeclamptic women (group 2= defined study group). Study group consisted of 43 patients with EOP and 37 patients with LOP. sVCAM-1 and fibronectin concentrations were measured by enzyme-linked immunosorbent assay (ELISA) and the findings were compared between the groups. Results: The mean levels of sVCAM-1 and fibronectin were significantly higher in the LOP group than those in the normotensive group (p = 0.043 and 0.010 respectively). Markers were significantly different between the two hypertensive groups of pregnancy. The EOP group had a higher level of sVCAM-1 and fibronectin concentration than the LOP group (p = 0.01, for both markers). There was a positive correlation both between the values of plasma fibronectin and the systolic- diastolic blood pressure measurements (r:0.43 and 0.44, respectively), and between sVCAM-1 and the systolic/diastolic blood pressure measurements (r = 0.54 and 0.64, respectively). Conclusion: Increased plasma levels of fibronectin and sVCAM-1 were found in the preeclamptic patients, especially in those with early-onset preeclampsia. These markers might be related to the pathogenesis of different types of preeclampsia.