Behçet's disease, mainly characterized by relapsing oral and genital ulceration and uveitis, also involves other tissues. In previous reports, the neuro-ophthalmologic manifestations of Behçet's disease are internuclear ophthalmoplegia, abducens nerve palsy, homonymous hemianopia and papillitis. Painful unilateral ophthalmoplegia is most often traceable to an aneurysm, a tumor, or an inflammatory or granulomatous process in the anterior portion of the cavernous sinus or at the superior orbital fissure. Behçet's disease presenting with painful unilateral ophthalmoplegia and optic neuropathy has not been previously reported. We report a case of painful unilateral ophthalmoplegia and optic neuropathy associated with Behçet's disease.