A lethal paradoxical air embolism (PLE) occurred in a 21-year-old secundigravida during general anaesthesia for cervical cerclage on account of cervical insufficiency. The diagnosis of PLE was verified postmortem; we initially diagnosed venous air embolism intraoperatively because of typical symptoms (cyanosis, pulmonary dysfunction, and vascular obstruction) and aspiration of air from the subclavian catheter. We also suspected an arterial embolism due to prominent neurologic deficits. In spite of corrective positioning, controlled ventilation (CPPV and PEEP), volume therapy, and sympathomimetics, resuscitation remained unsuccessful. This very rare complication depends upon several conditions: (1) opened, non-collapsible veins; (2) a pressure gradient from outside to inside the veins; (3) a patent foramen ovale; and (4) a right atrial pressure greater than that on the left, which can cause an air embolism to either the coronary or cerebral circulations. The pathophysiology and causative factors are discussed extensively as the immediately started resuscitation could not alter the lethal course.