A 46-year-old woman with systemic lupus erythematosus (SLE) and concomitant severe pulmonary hypertension (PH) is described. Other secondary causes of PH including thromboembolism, phospholipid syndrome, valvular disease and interstitial pulmonary involvement were ruled out. Owing to her lack of clinical response to conventional therapy, sildenafil was begun at increasing doses up to 400 mg daily. Both clinical and hemodynamic improvement ensued. This appears to be the first clinical report of the use of sildenafil in SLE followed by resolution of severe PH.