Twenty-five full-term newborns were compared to 20 premature newborns for several haemostatic parameters. The latter group exhibited no clinical symptoms of respiratory distress syndrome, except for two cases. The coagulative system was activated in either group. Differences were clearly recordable from the fibrinolytic system and indicated activation of fibrinolysis in full-term newborns and relative insufficiency of the same system in premature newborns. The need for assessment of both the coagulative system and fibrinolysis in any case of premature delivery is suggested by the authors and considered necessary for diagnosis, prophylaxis, and possible therapy of respiratory distress syndrome. Activation of fibrinolysis is interpreted as a mechanism of defence against concomitant intravascular coagulation, while the absence of compensation in the fibrinolytic system of the newborn is considered to be a mechanism which might lead to hyaline membrane syndrome.