The combination of nasal polyposis, thick tenacious mucin, crust formation and sinus cultures yielding “Aspergillus” was first noted by Safirstein, 1976, who observed the clinical similarity that this constellation of findings shared with allergic bronchopulmonary Aspergillosis. Reports that followed further supported the existence of this clinical entity, and gave rise to descriptive nomenclature such as “allergic Aspergillosis of the Paranasal sinuses”,“allergic fungal rhino sinusitis”, and most recently “eosinophilic fungal rhino sinusitis”. Typical patients with allergic fungal rhino sinusitis are immune competent young adults with recurrent chronic sinusitis, massive nasal polyposis, and thick tenacious mucin in the nose and sinuses. They may have history of multiple sinonasal surgical procedures or history of documented atopic disease, peripheral eosinophilia and elevated total IgE level. Most authors agree that AFS is an underdiagnosed entity and that only an increased awareness among physicians to look for fungal involvement will increase the accuracy of diagnosing AFS. Unfortunately, previous diagnostic methods seem to lack sensitivity. For example, in the past, even when fungal hyphae were clearly identified in histologic specimens, only 60% of the cultures were positive for fungi.