From April 18 to May 31, 2003, 46 patients with probable severe acute respiratory syndrome were admitted to the negative-pressure isolation rooms of Mackay Memorial Hospital in Taipei, Taiwan. Their demographic, clinical, laboratory, and radiologic characteristics and clinical outcomes were analyzed. There were 15 males and 31 females, in this cohort, 13 of whom were healthcare workers. The latter included 6 hospital staff and 7 medical personnel transferred from other hospitals. The most common symptoms were fever (100%, 46/46), cough (72%, 33/46), shortness of breath (46%, 21/46), and diarrhea (39%, 18/46). Other common findings were lymphopenia (57%, 26/46), thrombocytopenia (39%, 18/46), elevated lactate dehydrogenase (63%, 29/46), and elevated creatine kinase (24%, 11/46). A total of 7 patients (15%) required mechanical ventilation, and 8 (17%) died. Advanced age was an independent significant risk factor for death. Fever followed by rapidly progressive respiratory compromise led to significant morbidity and mortality in this cohort.