Fungal infections could play a role in chronic obstructive pulmonary disease (COPD) patient's exacerbations and in lung function impairment. In fact, Aspergillus fumigatus is often isolated from respiratory samples, but few data are available about its clinical significance. Aspergillus colonization could be associated to a higher risk of invasive pulmonary aspergillosis (IPA), which, in COPD patients, is characterized by a 2% incidence (probably underestimated) and a high mortality (72 to 95%). Similarly, detection of anti-Aspergillus antibodies is quite frequent in COPD patients but its significance and usefulness for aspergillosis diagnosis and follow-up have not been assessed. Furthermore, several studies suggest a frequent carriage of Pneumocystis jirovecii, reaching 37-55%, with a higher frequency in the most severe COPD stages and a possible role of colonisation in the occurrence and progression of COPD.