Neonatal intracranial aneurysms are rare. The authors report the case of a 4-week-old girl who presented with left-eye ptosis and proptosis. Computerized tomography scanning and magnetic resonance imaging demonstrated a mass involving the left cavernous sinus and middle cranial fossa. Cerebral angiography revealed a large complex left cavernous carotid artery (CA) aneurysm. The patient underwent endovascular treatment in which detachable coils and N-butyl cyanoacrylate glue were used to achieve complete obliteration of the aneurysm. To the authors' knowledge, this is the first reported neonatal intracranial aneurysm originating from the cavernous CA and treated endovascularly. The authors review the literature on neonatal intracranial aneurysms.