We describe a large series of patients with chronic obstructive pulmonary disease (COPD) and probable invasive pulmonary aspergillosis (IPA), and the risk factors and incidence of the disease in patients with isolation of Aspergillus from lower respiratory tract samples. From 2000 to 2007, we retrospectively studied all patients admitted with COPD and isolation of Aspergillus (239; 16.3/1000 admissions). Multivariate logistic regression and survival curves were used. Fifty-three patients had probable IPA (3.6 cases of IPA per 1000 COPD admissions). IPA affects at least 22.1% of patients with COPD and isolation of Aspergillus in culture. In 33 of the 53 patients with probable IPA, serum galactomannan was determined; in 14 (42.4%) of these, the result was positive. Five variables were independent predictors of IPA with statistical significance: admission to the intensive-care unit, chronic heart failure, antibiotic treatment received in the 3 months prior to admission, the accumulated dosage of corticosteroids equivalent to >700 mg prednisone received in the 3 months prior to admission, and the similar accumulated dosage of corticosteroids received from admission to the first clinical isolation of Aspergillus. Multivariate analysis gave an area under the curve of 0.925 (95% CI 0.888-0.962; p <0.001). The overall mean survival of the cohort was 64.1% (28.3% for IPA patients and 75.2% for non-IPA patients). The median number of days of survival was 48 (95% CI 33.07-62.92). However, we found statistically significant differences between patients with IPA (29 days; 95% CI 20.59-37.40) and patients without IPA (86 days; 95% CI 61.13-110.86) (log rank, p <0.001).