Opic neuritis is a rare disease that is seen with acute loss of visual acuity and color vision, a central scotoma, and retobulbar pain. The cause of optic nueritis is uncertain in many patients, but it is important to find out the associated medical conditions. Among the known causes of optic neuritis, multiple sclerosis remains the most common cause, but many other causes have been suggested. The disease of paranasal sinuses is an infrequent, but treatable, cause of optic neuritis. There is much speculation about the pathophysiological mechanisms which relate these two distinct disease entities. These include compressive optic neuropathy secondary to mucocele and/or pyocele, direct extension of sinus infection to the optic nerve from suppurative paranasal sinusitis and from osteomyelitis of the ethmoid and sphenoid sinusitis, and bacteremia through the thrombophlebitis. But some patients with optic neuritis that is related to the disease of paransal sinuses have no nasal symptoms and signs, the usefulnes of computerized tomography of the orbits and paranasal sinuses to evaluate optic neuritis and to elucidate in detail the pathophysiology of its relationship to the disease of paranasal sinuses is emphasized. It is important to remove the disease of paranasal sinuses surgically as soon as possible for the good prognosis, if the optic neuritis cannot effectively be improved by medical treatment. Recently the authors experienced a case of rhinogenic retrobulbar optic neuritis due to pyoceles in posterior ethmoid and sphenoid sinuses that have no nasal symptoms and signs and showed rhinoscopically normal findings. We report its clinical manifestations and characteristics with a review of literature.