Oncologic therapy creates a highly vulnerable group of children with little or no natural immunity. In addition to the problems of coagulopathies, these children are prone to unusual infectious diseases. One group of saprophytic infections, the mycotic organisms, represents stubborn and often lethal diseases challenging present diagnostic and therapeutic skills. This is a case report of invasive Aspergillus organisms in the nose and premaxilla in a 9-yr-old child suffering from acute monocytic leukemia.