Carotid cavernous fistula is a well-documented but rare condition in pregnancy, about which there are a limited number of reports in the literature. We report such a case in a 41-year-old woman presenting with right-sided headache, proptosis, and diplopia at 37 weeks of gestation. She was subsequently diagnosed to have carotid cavernous fistula based on angiography. Embolisation was performed in the postpartum period. Carotid cavernous fistula has the potential of serious morbidity including visual loss and intracranial haemorrhage. It can be treated effectively by endovascular embolisation, which confers a good prognosis. Although headache is a common complaint during pregnancy, obstetrician should be aware of this condition if the clinical presentation is suspicious.