Background: Two major complications of Aspergillus SENSITIZATION in patients with asthma, including severe asthma with fungal SENSITIZATION (SAFS) and asthma associated with fungal SENSITIZATION (AAFS), have been recently described. Objectives: In the present study, we aimed to evaluate the prevalence of SAFS and AAFS in Iranian patients with asthma. Methods: Two hundred consecutive outpatients aged 18 years with moderate to severe allergic asthma, referred to a pulmonary subspecialty hospital (Tehran, Iran) for 25 months, were included in the study. Skin prick test (SPT), total IgE (tIgE), and specific IgE (sIgEAf ) and IgG against Aspergillus fumigatus (sIgGAf ) were determined for all subjects. Comprehensive criteria were applied for the diagnosis of SAFS and AAFS. Results: Of 200 included patients, 103 (51. 5%) and 97 (48. 5%) were with moderate and severe asthma, respectively. Of these patients, 111 (55. 5%) were female. The mean (range) of age was 45. 8 (18-78) years. Of 200 patients, 27 (13. 5%), 22 (11. 0%), 114 (57. 0%), and 131 (65. 5%) were positive for Aspergillus SPT, sIgEAf, sIgGAf, and tIgE, respectively. The overall prevalence of SAFS in patients with severe asthma and AASF in patients with moderate asthma were 7. 2% (7/97) and 3. 9% (4/103), respectively. Conclusions: According to the findings, the prevalence of SAFS and AAFS in Iranian patients with severe and moderate allergic asthma was lower than the previously published global data. This low-prevalence reported rate may be due to the fact that we applied strict criteria in the present study.