This case report describes massive fibrinolysis after prolonged cardiopulmonary resuscitation. Lab results revealed unexpected clotting abnormalities, with infinitely prolonged clotting times and an immeasurably low fibrinogen concentration. Severe haemorrhage occurred with haemodynamic instability and failure of mechanical ventilation. Post mortem, the observed clotting abnormalities where interpreted as hyperfibrinolysis, caused by hypoperfusion. This mechanism, and other causes of abnormal haemostasis post-resuscitation, are discussed in this paper. Hyperfibrinolysis is associated with severe hypoperfusion leading to endothelial damage and glycocalyx breakdown and correlated with lactate levels and chest compression times. Significant fibrinolysis after cardiopulmonary resuscitation occurs more frequently than clinicians may think, and thromboelastography might be useful to detect and possibly treat hyperfibrinolysis early. In this case, severe haemorrhage was the immediate cause of death after successful return of spontaneous circulation. © 2016, Netherlands Society of Intensive Care. All rights reserved.