Dural carotid-cavernous sinus fistula (d-CCF) is a rare cause of ophthalmoplegia, and it may be overlooked when the prominent external orbito-ocular sign is lacking. Conventional angiography is the gold standard in the diagnosis of d-CCF. Recently, the specific MR findings of d-CCF have increasingly been reported. We report a patient with spontaneous d-CCF presenting with an isolated fourth-nerve palsy in whom magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) demonstrated d-CCF. Key Words : Carotid cavernous sinus fistula, Ophthalmoplegia, Angiography, Magnetic resonance imaging, Magnetic resonance angiography