Objective. To evaluate optical rhinometry (ORM) using nasal provocation testing (NPT) as an objective tool to diagnose fungal allergic rhinitis (AR). Study Design. Prospective. Setting. Tertiary academic center. Methods. We prospectively enrolled healthy controls (HCs) and subjects with a clinical history of AR and positive skin prick test to Alternaria or Aspergillus antigens. Baseline measurements with an optical and acoustic rhinometer (AcR) were taken, and all subjects underwent NPT with increasing concentrations of Alternaria and then Aspergillus in each nasal cavity. Optical density (OD), nasal mean cross-sectional area (MCA), visual analog scale (VAS), and nasal allergen provocation scale (NAP) were measured after each provocation. A NAP score ≥ 3 was considered positive. Receiver operating characteristic (ROC) curve analysis was performed on measured parameters. Results. Eleven HCs and 11 AR subjects were enrolled. Of the 8 AR patients with an Alternaria-positive skin test, 50% had a positive NAP score (4/8) vs 0% in HCs (0/11, P = .01). Although VAS could differentiate Alternaria-sensitive patients from controls, change in OD and MCA could not. Of the 7 skin test - positive Aspergillus patients, 43% had a positive NAP score (3/7) vs 0% in HCs (0/11, P = .02). The VAS and change in OD and MCA did not differentiate Aspergillussensitive patients from controls. Conclusion. In this study, fungal antigens caused irritation but did not elicit early phase changes in nasal patency or blood flow in fungal-sensitive AR patients. The poor correlation of skin testing and objective nasal response to fungi argues against a pure IgE-mediated immune response in the nasal cavity. © American Academy of Otolaryngology - Head and Neck Surgery Foundation 2013.