Severe acute respiratory syndrome (SARS) is a serious respiratory illness caused by a novel human coronavirus. The disease is highly infectious and carries significant mortality and morbidity. There was a major outbreak of SARS in Guangdong, Taiwan, Beijing, Hong Kong and Toronto between March and June 2003. Common presenting features of SARS are high fever, chills, rigor, malaise, nonproductive cough, lymphopenia and pulmonary infiltrates, followed by rapidly progressive respiratory failure in some cases. We describe two patients with systemic lupus erythematosus (SLE) who presented with fever, systemic upset and pulmonary infiltrates between April and June, 2003. One patient was confirmed to have coronavirus pneumonia while the other had active SLE with lung involvement. Our cases illustrate the difficult diagnostic dilemma in the evaluation of febrile SLE patients during the SARS epidemic.