Abstract： Objective To explore the clinical and radiological features of severe acute respiratory syndrome (SARS). Methods Analysis of the clinical presentation, chest radiographs, course of disease and features of severe pneumonia in 45 SARS patients diagnosed at our hospital in Beijing between April 5-20, 2003. Also included is a summation of the clinical features of SARS.Results (1) SARS appears to have high infectivity; (2) the most common symptom is fever;(3) the count of leukocyte is normal or decreased; (4) most patients (35/45, 77.8%) had experienced a 24-hour fever prior to the abnormal chest X-ray changes which showed progression of pulmonary infiltrates within 48 hours in 71.1% (32/45) of the patients and, (5) the percentage of patients who developed severe pneumonia (24.4%) is higher than those who developed typical pneumonia.Conclusion SARS is a disease with high infectivity and has its own clinical and radiological features. Early recognition, prompt isolation, and appropriate therapy are the key to combate this infection.