BACKGROUND: In this study we evaluated the incidence of invasive pulmonary aspergillosis among intubated patients with critical coronavirus disease 2019 (COVID-19) and evaluated different case definitions of invasive aspergillosis. METHODS: Prospective, multicentre study on adult patients with microbiologically confirmed COVID-19 receiving mechanical ventilation. All included participants underwent screening protocol for invasive pulmonary aspergillosis with bronchoalveolar lavage galactomannan and cultures performed on admission at 7 days and in case of clinical deterioration. Cases were classified as coronavirus associated pulmonary aspergillosis (CAPA) according to previous consensus definitions. The new definition was compared with putative invasive pulmonary aspergillosis (PIPA). RESULTS: A total of 108 patients were enrolled. Probable CAPA was diagnosed in 30 (27.7%) of patients after a median of 4 (2-8) days from intensive care unit (ICU) admission. Kaplan-Meier curves showed a significant higher 30-day mortality rate from ICU admission among patients with either CAPA (44% vs 19%, p= 0.002) or PIPA (74% vs 26%, p<0.001) when compared with patients not fulfilling criteria for aspergillosis. The association between CAPA [OR 3.53 (95%CI 1.29-9.67), P=0.014] or PIPA [OR 11.60 (95%CI 3.24-41.29) p<0.001] with 30-day mortality from ICU admission was confirmed even after adjustment for confounders with a logistic regression model. Among patients with CAPA receiving voriconazole treatment (13 patients, 43%) A trend toward lower mortality (46% vs 59% p=0.30) and reduction of galactomannan index in consecutive samples was observed. CONCLUSION: We found a high incidence of CAPA among critically ill COVID-19 patients and that its occurrence seems to change the natural history of disease.