A case of Sjögren's syndrome with optic neuropathy and acute transverse myelopathy mimicking multiple sclerosis is described. The patient suddenly lost her visual acuity resulting in a permanent visual deficit in spite of the massive steroid therapy given. During the treatment the patient showed dry eye symptoms and was finally diagnosed as having primary Sjögren's syndrome. It is suggested that primary Sjögren's syndrome should be considered in the differential diagnosis of neurologic disorders that resemble multiple sclerosis.