Abstract Objectives: To determine parameters that predispose toward invasive fungal sinusitis (FS)in immunocompromised patients Methods: We conducted a retrospective chart review of 10 patients with lymphoproliferative disorders who developed invasive FS and compared them to 20 subjects with lymphoproliferative disorders who did not develop invasive FS. Signs and symptoms, endoscopic findings, radiographic findings, anatomic location of the lesions, absolute neurophil counts, medication preceding presentation, treatment, and outcome of the 2 groups were compared. Results: Fever and facial pain are the most common complaints in both patient groups. All patients had evidence of neutropenia and absent absolute neutrophil counts (ANC). Endoscopy in those patients with FS demonstrated mucosal edema, crusting, or white exudate. A general anesthetic was required for every endoscopy. Radiographic abnormalities were found in both groups and did not aid in FS diagnosis. Conclusions: Immunocompromised patients who present with fever or facial pain and neutropenia need to be evaluated promptly for possible FS. Endoscopic abnormalities were found to be the most reliable indicator of FS in this group of patients. In pediatric patients, a general anesthetic should be considered to enhance optimal endoscopic examination and facilitate nasal biopsies.