Methods: cross-section, description, analysis in all patients with severe pneumonia admitted to Respiratory Department, Cho Ray hospital form July 2007 to June 2008.Results: 217 cases of severe pneumonia were enrolled, overall mortality was 72 (33.2%), 77 (35.5%) cases improved clinical symptoms without changing the initial antibiotic, 68 (31.3%) must be changed antibiotics to improve clinical signs and symptoms.