The patient was a 33 year female. In 2001, she was diagnosed with systemic lupus erythematosus (SLE) and treated with prednisolone and ciclosporin. In May 2006, she noticed slight muscle weakness in the bilateral lower limbs. In July of the same year, she experienced gait difficulty and was admitted to our hospital because of fatigue, appetite loss, fever and disorientation. Soon afterwards, she had a fit of general convulsion and suffered from urinary retention and fecal incontinence. A brain magnetic resonance image revealed atrophy of the thoracic cord in T2 weighted images, and cerebrospinal fluid examination showed high total protein and interleukin-6 concentration, indicating complication of lupus myelitis as well as cerebral involvement. Steroid pulse and oral prednisolone treatment resulted in ameriolation of cerebral complications such as disorientation and convulsion, but muscle weakness and paresthesia in the lower limbs and urinary retention persisted. Cyclophosphamide pulse therapy was started and resulted in a marked recovery from muscle weakness, paresthesia and urinary retention, and she could discharge. We conclude that steroid and cyclophosphamide pulse therapy for a SLE patient with CNS lupus and lupus myelitisis is effective for ameriolation of symptoms such as disorientation, convulsion, urinary retension, fecal incontinence, muscle weakness and paresthesia in the lower limbs as well as elevated level of serum anti-ribosomal P antibody.