Aspergillus lentulus was first described in the year 2005, and since it cannot be phenotypically distinguished from Aspergillus fumigatus, it is conceivable that earlier descriptions (before 2005) could be attributed to this new species. Currently invasive infections caused by A. lentulus are rare and very few cases have been previously published in neutropenic patients, all of them with fatal outcome. Here we report a critically ill non neutropenic patient with chronic obstructive pulmonary disease (COPD) who was admitted to the medical intensive care unit with an exacerbation of COPD and who had been treated with long term corticosteroids. A. fumigatus was cultured from two bronchial aspirates and in a third bronchial aspirate both A. lentulus and A. fumigatus were isolated. On two consecutive days detection of galactomannan in serum was negative whilst detection of (1-3) beta-D glucan was positive (> 518 pg/ml). Minimal inhibitory concentrations (MIC) for itraconazole, voriconazole, caspofungin and amphotericin B were high for this strain of A. lentulus. Given the high MIC values of A. lentulus to available antifungals, the accurate identification of this new species is warranted. To our knowledge, this is the first report of the isolation of A. lentulus in a non-neutropenic critically ill patient, although we note that since it was isolated only once from respiratory specimens, its implication as an etiologic agent of infection for this patient remains to be established.