Aneurysmal subarachnoid hemorrhage (aSAH) is a rare but devastating complication with increased morbidity and mortality. It is still unclear whether the incidence is increased during pregnancy and in the peripartum period. However, the incidence of cerebral aneurysmal rupture is higher during the third trimester than in the first trimester. The risk of aneurysmal rupture and subarachnoid hemorrhage (SAH) during general anesthesia or spinal anesthesia is unclear. We report a case of left supraclinoid aneurysm rupture after spinal anesthesia for Low Segment Caesarean Section (LSCS) in the immediate postpartum period causing high-grade aSAH.