The epidemiology of chronic obstructive pulmonary disease (COPD) in critically ill patients is largely unknown. The aims of the study were: 1) to determine whether COPD, either as the cause of intensive care unit (ICU) admission or as a comorbid condition, is an independent risk factor for increased morbidity and mortality; and 2) to investigate time trends in proportion and outcome of acute respiratory failure in patients with COPD admitted to ICUs. Prospectively recorded data from 194 453 adults consecutively admitted to 87 Austrian ICUs over a period of 11 years (1998-2008) were retrospectively analysed. COPD was present in 8.6% of all patients. The risk-adjusted mortality of patients with COPD was higher than in patients without COPD. The presence of COPD was an independent risk factor for increased mortality and was associated with prolonged mechanical ventilation and prolonged weaning. During the course of the 11 years, the proportion of acute respiratory failure due to COPD increased by about two-thirds, and the use of noninvasive ventilation within the COPD cohort more than doubled. Simultaneously, the risk-adjusted mortality of patients with COPD improved. In critically ill patients, the presence of COPD is increasing and is an independent risk factor for mortality and morbidity.