We reported a 68-old female who was diagnosed to have systemic lupus erythematosus 18 years ago. She had been well under 5 mg of prednisolone until 1995, when she felt severe shortness of breath. Laboratory examinations disclosed severe anemia accompanying mild thrombocytopenia. Bone marrow aspiration revealed a complete absence of erythroid progenitor cells. She was diagnosed to have pure red cell aplasia (PRCA) as well as antiphospholipid syndrome. A judicious use of methylprednisolone including pulse therapy resulted in a prompt resolution of anemia as well as thrombocytopenia and the dose of corticosteroid was tapered successfully thereafter. Persistent infection of HPV B 19 in the patient with inactive SLE was considered as a main cause of PRCA because not only IgG-HPV B 19 antibody but viral DNA was demonstrated in her serum at the time of admission. The relationship between PRCA and anti-phospholipid syndrome in this patient was also noted.