Acquired spontaneous hemophilia is a rare but potentially life-threatening disease, which poses a major challenge to intensive care medicine. We report a case in which the disease occurred postoperatively in a patient following uncomplicated lumbal discectomy. The clinical sequelae involved hemorrhagic shock (cHb 4.1 g/dl; hct 17 %; systolic BP 60 mmHg; HR 130/min; saO2 73 %) due to retroperitoneal hematoma eight days after neurosurgical intervention. While lesions of the retroperitoneal vessels were not found during emergent angiography and laparotomy, the laboratory results showed a slightly prolonged activated prothrombin time (aPTT; 47 s). However, application of fresh frozen plasma (FFP) even prolonged the aPTT (53 s). Analysis of clotting factors proved a deficiency of factor VIII with a reduced activity of about 20 %, which was resistant against therapy with desmopressin (DDAVP) and substitution of factor VIII. Thus, the plasma-mix-test was performed, showing complete inactivation of the factor VIII-activity of the pooled plasma. This evidenced the presence of acquired inhibitors against factor VIII. Hemostasis was successfully and immediately restored with the application of recombinant factor VIIa (rFVIIa), including boluses of 60 - 80 microg/kg every 6th - 8th hour (supplemented with tranexamic acid, 3 x 1 g/d), leading to a continuous infusion of 12 microg/kg per hour. With prednisolone (1 mg/kgBW/d) over the ensuing 8 weeks, the antibodies were sufficiently suppressed and no additional substitution of factor VIII was necessary to maintain normal hemostasis.