Thrombolytic therapy during cardiopulmonary resuscitation is not routinely recommended, but 50-70% of cardiac arrests are caused by either acute myocardial infarction or massive pulmonary embolism. Thrombolytic therapy can be a reasonable treatment modality for a patient suffering with cardiac arrest in an emergency situation and whose diagnosis is not known. We report here on a case with cardiac arrest and the diagnosis was not known. The patient was refractory to conventrional cardiopulmonary resuscitation, and he was treated with a bolus injection of a thrombolytic agent. He recovered completely without complications.