Summary Objective: The effects of three types of low-dose oestrogen oral contraceptives (OC) with different newly-developed progestagen components on the fibrinolytic system were compared. Design: Open randomized comparative study. Subjects and interventions: Three groups of healthy female volunteers (n = 20 per group) received one of the following third generation OC: Cileste (35 mg ethinyloestradiol EE, 250 mg norgestimate), Tri-Cileste (35 mg EE, 180/215/250 mg norgestimate), or Triodena (30/40/30 mg EE, 50/70/100 mg gestodene). Results: Systemic levels of fibrinolysis activation markers plasmin-antiplasmin-complex and fibrin split product D-Dimer increased during OC treatment, suggesting a treatment-induced activation of this enzyme system (P Conclusion: Our results suggest that during treatment with the third generation OC Cileste, Tri-Cileste, and Triodena a similar activation of fibrinolysis occurs and thus a comparable compensation for the known triggering effects of these drugs on blood coagulation can be assumed.