We report a 35-year-old parturient with gestational diabetes mellitus (GDM) history who sustained a nearly fatal Bezold-Jarisch reflex during Cesarean section under spinal anesthesia. A high spinal block combined with acute massive hemorrhage may produce life-threatening Bezold-Jarisch reflex which should be treated prophylactically and aggressively during surgery. Additionally, the autonomic disturbance associated with GDM might exaggerate the reflex in this episode. The patient survived after successful resuscitation and was discharged without any sequela.