A patient with a history of facial myokymia presented with apoplectic headache and a 3rd nerve palsy. Initial CT, lumbar puncture, and cerebral angiogram were unremarkable, but subsequent CSF examination revealed oligoclonal bands. MRI displayed over 30 white matter lesions. This case demonstrates that multiple sclerosis may present with severe headache and a 3rd nerve palsy, simulating the clinical picture of a posterior communicating artery aneurysm.