While the majority of spinal epidural hematomas after a spinal operation are clinically asymptomatic, the reported percentage of hematomas needing surgical evacuation is only 0.1 %. A 69-year old woman presented after a rapidly progressive worsening of her neurologic status at both legs. The patient was under anticoagulant medication with acenocoumarol due to atrial fibrillation and underwent a decompression laminectomy and L5, S1 left nerve root decompression. Eleven hours after the operation she presented with acute progressive cauda equina syndrome due to an epidural hematoma and was immediately transferred to the operating theater. A membrane of white clot was found and the presence of epidural clotted blood beneath the membrane was verified. The surgeon must be aware of this catastrophic complication that requires a high level of suspicion and prompt intervention. Large, multicentre prospective, randomized studies are needed to fully investigate the risks of anticoagulation therapy after spinal surgery.