It is a unique work dealing with human aspergillosis. It is the first study on aspergillosis at Assiut University Hospitals. In this piece of work, you will find an interesting record on the incidence of mycobiota incriminated for the disease, a new method to diagnose aspergillosis in ventilated patients and a study of risk factors affecting the disease. Potentialities of the isolated aspergilli for enzymes and mycotoxins production and the efficacy of some selected antifungals in vivo and in vitro are also included.