Respilc!tory tract infection is the most common cause of COPD exacerbation. In addition, CRP is an inflammatory protein and a marker for inflammation. Objectives: Comment clinical, paraclinical characteristics and serum CRP concentrations of patients with COPD exacerbation. Subject and research method: Inpatients were diagnosed COPD exacerbation at the Respiratory center - Bach Mai hospital. Retrospective descriptive, convenience sample. Results: the average age: 67.37 ' 9.67 years old, most patients were over 60 years old (82 percent). Male accounted for 96 percent. 97 percent of patients hospitalized for dyspnea, 95 percent of patients had cough, 86 percent of patients had increased sputum production. The common para clinical tests were increased WBC (53.1 percent), increased serum CRP concentration (53.9 percent). The was no association between CRP levels and age, disease stage. The common lesions in chest imaging were emphysema
(54.3 percent), dirty chest (22.81 percent), tear-drop heart (17.54 percent), inflammatory opacities (17.54 percent). The majority was IV stage (74.4 percent). The main cause of COPD exacerbation was respiratory tract infection (74 percent). Some other causes were cardiac arrhythmia (10 percent), worsening heart failure (2 percent), pneumothorax (2 percent) and unknown (12 percent). Conclusions: By studying 100 inpatients with COPD exacerbation at the Respiratory - Bach Mai hospital, the authors draw some following conclusions: Majority of patients with COPD were male, almost patient hospitalized for dyspnea and increased sputum cough. The most common lesion on chest xray was emphysema. Most of patients had increased WBC and serum CRP concentration. CRP levels tend to rise, according to disease stage and severity of exacerbation but there was no strict correlation between these factors. The cause of COPD exacerbation was mainly infection.