Abstract: Aim: To investigate changes in various parameters of the fibrnolytic system of patientswith pregnancy induced hypertension (PIH). Methods: The values of D - dimer (D - D), fibrin degradation products (FDP), fibrinogen (Fg), tissue plasminogen activator (t - PA) and a2 - plasmin inhibitor (a2 - PI) activity were determined in 20 normal pregnant women and 15 patients with PIH. Results: The value of D - D showed significant difference between nonpregnant and normal pregnant women(P 0 .01) and very significant difference between normal pregnant women and patients with PIH (P 0.001); the 100% appearance of FDP in PIH patients was significantly higher than that of 15% seen innormal pregnant women; the fibrinogen level showed significant diffevence between the above three groupsof women (P 0.01); the t - PA value showed no substantial difference between nonpregnant and normal pregnant women, but significant difference between the latter group and patients with PIH (P0.001); a2 - PI activity exhibited no significant difference between the three groups. Conclusion: Normal pregnant women are in a hypercoagulable stste and the PIH patients show a tendency to develop thrombosis and predispose to spontaneous intravascular coagulation, moreoverl the parameters D - D and activityof t - PA and of a2 - PI are molecular markers of the fibrinolytic system and can be applied to monitor thechanges in fibriolysis and thrombosis in PIH patients.