Heparin-induced thrombocytopenia (HIT) is a rare immune-mediated complication of heparin administration. A potentially life-threatening complication, HIT is difficult to diagnose in patients in the intensive care unit after cardiac surgery because there can be multiple reasons for thrombocytopenia. Moreover, immune-mediated platelet consumption may be masked by reactive thrombocytosis, which is common in the typical postoperative course after cardiac surgery. We report the case of a 57-year-old male patient who developed fulminant pulmonary embolism following heparin-induced thrombosis without thrombocytopenia after off-pump coronary artery bypass surgery.