A 28-year-old man presented with headache, fever, and myalgia. Subsequently, rapidly progressive quadriplegia withareflexia developed. CSF examination revealed moderate pleocytosis and protein elevation. MRI of brain and spinalcord showed hyperintense lesions on T2-weighted image at midbrain and ventral horns along the whole spinal cord.Serial serologic examinations of CSF for Epstein-Barr virus and cytomegalovirus were negative. Culture and neutralizationtests of stool and CSF for enterovirus were negative. Although the etiologic pathogen was not identified, we diagnosedhim as poliomyelitis-like syndrome by clinical features and findings of MRI.