Protein Z (PZ) is a 62 kDa vitamin K-dependant glycoprotein, synthesized by the liver. PZ has shown to possess procoagulant as well as anticoagulant properties. First PZ enhance the assembly of thrombin with phospholipids surface thus enhancing coagulation. Secondly, it is responsible for binding of PZ dependant protease inhibitor to factor Xa and therefore indirectly act as a natural anticoagulant. High PZ plasma levels may represent a prothrombotic conditions in preeclamptic patients. Thus, estimation of PZ plasma levels is of utmost importance for early diagnosis of preeclampsia before 20th week of gestation. The (A) allele of an intron F polymorphism appears to be a novel protective genetic marker for the risk of preeclampsia being associated with low PZ plasma levels.