A 16-year-old girl was admitted to our hospital in August 23, 1986, for headache, nausea and low grade fever. Marked increases in immunoglobulin indices were found in the cerebrospinal fluid. When she was 13, she was diagnosed as having SLE and lupus nephritis. On September 9, 1986, she complained of urinary retention, and pathological reflexes were elicited bilaterally. On September 13, she complained of a sudden loss of vision (count fingers) in the right eye which worsened to a visual acuity of light perception over the next 48 hours. A visual evoked response potentials (VEP) to flash stimulation gave a loss of amplitude and an increase in latency. On September 16, she complained of a similar loss of vision in the left eye. Leakage of dye around the left optic disc was found by a fluorescein angiogram on September 26. These results indicated a diagnosis of bilateral optic neuritis. Both visual acuity returned rapidly over the following month following oral prednisolone treatment. Optic neuritis is an exceedingly rare complication in SLE. Although the visual prognosis have been fairly good in the reported cases, some have resulted in various states of blindness. As for etiology of optic neuritis in our patient, ischemic change of optic nerves due to microvasculopathy as well as slight demyelinating process were speculated by the VEP pattern.