The authors describe an 11-year-old girl with systemic lupus erythematosus (SLE) who developed simultaneous bilateral acute optic neuritis. Severe initial visual loss followed by permanent visual deficit occurred in both eyes despite therapeutic intervention. Recurrence of optic neuritis in one eye caused the vision to deteriorate further. The most probable pathogenesis is occlusive vasculitis involving the small arterioles of the optic nerves.