Aspergillosis is becoming an increasingly recognized pathogen in the sinonasal tract. The courses of two patients, one seemingly healthy and one with a terminal malignancy, are reviewed. These patients illustrate the clinical course, difficulties in diagnosis, and management of patients with aspergillosis of the sinonasal tract. Aspergillus is a common endogenous contaminant of the upper respiratory tract; however, bacterial sinusitis may trigger its growth and proliferation. Aspergillus fumigatus is the most common species implicated in paranasal sinus disease in the United States. The maxillary antrum is the most commonly involved site in the paranasal sinuses. Originally, aspergillosis was described in healthy patients, but it has become increasingly recognized in the immunocompromised and the chronically debilitated. Paranasal sinus Aspergillus infections are classified as non-invasive and fulminant. The treatment is primarily surgical. Antifungal chemotherapeutic agents are used in the treatment of central nervous system involvement and in the fulminant form of the disease.