Anautopsied case of systemic lupus erythematosus with pulmonary hypertension is reported. A 29-year-old womanwith a seven-year history of polyarthralgia, butterfly rash, nephrotic syndromeand Raynaud's phenomenonwas admitted because of progressive dyspnea on exertion. Tests for antinuclear antibody, anti-cardiolipin antibody and lupus anticoagulant were positive. Echocardiographic examination revealed right ventricular hypertrophy and a moderate pericardial effusion. Estimated systolic pulmonary arterial pressure was 53 mmHg.Despite treatment with corticosteroids including pulse methylprednisolone therapy, lipo-PGEi and warfarin, she died of progressive congestive heart failure. Postmortem examination of the pulmonary vasculature revealed findings consistent with plexogenic pulmonary arteriopathy, without evidence ofvasculitis, fibrinoid necrosis, or thromboemboli. (Internal Medicine 33: 540-542, 1994)