Several parameters of hemostasis have been studied in 19 patients suffering from abruptio placentae. In 10 of them severe hemostatic alterations were detected and in 5, disseminated intravascular coagulation was observed. The patients were divided into four groups according to the severity of their clinical picture. The degree of placental separation was related to the severity and course of the clinical history and to the alterations in hemostasis detected at the most critical clinical moment. The analytical parameters were evaluated after extraction of the thromboplastic material. A good correlation was observed between the severity of the clinical picture and the degree of placental separation and the greatest analytical alteration, especially with cross-linked soluble fibrin monomer complexes (SFMC). In 9 of the 19 patients who showed analytical and/or clinical alterations, an improvement was detected in these alterations after evacuation of the uterus.