Disturbances in the blood coagulation mechanism arc seen by the obstetrician and gynecologist as rare complications of abruptio placentae, retained dead fetus syndrome, amniotic fluid embolism, toxemia, saline amnioinfusion, and septic abortion. Two cases of disseminated intravascular coagulation complicating gynecologic malignancy arc presented. Laboratory studies showed thrombocytopenia, hypofibrinogenemia, and increased fibrin degradation products. Derangements of hemostasis in patients with malignancy arc discussed from a clinical viewpoint.