We describe a 58-year old patient with chronic lymphocytic leukemia (CLL) who developed systemic lupus erythematosus (SLE) with severe joint involvement. Dilated myocardiopathy precluded the use of high corticoid doses and a 15 days of prednisone (15mg/d) had no effect on the polyarthritis. Therefore, fludarabine (25mg/m2) was administered for 5 d. One month after the first cycle, fever, muscle stiffness and polyarthritis resolved. A total of 6 cycles were administered. The evolution was complicated by herpes zoster infection and left pneumococcal pneumonia. At this time of writing (July 1999), the patient is symptom free but is profoundly lymphopenic.