Background Acute exacerbation of chronic obstructive pulmonary disease (COPD) is always associated with a high incidence and mortality. Because of the presence of some concomitant risk factors such as immobilization, bronchial superinfection, patients who are admitted for acute exacerbations of COPD are generally considered to be at moderate risk for the development of venous thromboembolism. In this study, we investigated the prevalence and the clinical manifestations of deep venous thrombosis (DVT) in patients with acute exacerbation of COPD.Methods From March 2007 to March 2009, 520 consecutive patients were included in this study. On admission, color Doppler ultrasound of lower extremities in all cases was performed for diagnosing DVT. Patients with DVT were compared with those without DVT from such aspects as demographics, symptoms, physical signs and risk factors.Results Among the 520 patients, DVT was found in 46 cases (9.7%). In patients with DVT, the duration of hospitalization was longer (P=0.01), and the mechanical ventilation requirement increased (P <0.001). Other indicators for patients with more possibility of DVT were immobility exceeding 3 days (P <0.001); pneumonia as concomitance (P=0.01); respiratory failure type Ⅱ (P=0.013); current smoking (P=0.001). Lower extremity pain was more common in DVT cases in comparison to those without DVT (34.8% vs. 15.2%, P=0.01 ).Conclusions The acute exacerbation of COPD patients, who were immobilized for over 3 days, complicated by pneumonia and had respiratory failure type Ⅱ, had a higher risk of DVT. In addition, DVT detection awareness should be increased in cases that had a lower extremity pain.