This work is part of a study demonstrating that the fungus Nannizziopsis guarroi is the cause of the disease known as yellow fungus disease in bearded dragons (Pogona vitticeps) by fulfilling Koch’s postulates. In this study, bearded dragons were exposed to N. guarroi to assess gross and microscopic lesion development and the ability to re-culture the fungus from infected sites. At euthanasia, skin and internal organs were collected and fixed in 10% neutral buffered formalin for histopathological assessment. Slides were processed and stained with periodic acid-Schiff as per standard procedure (Luna 1968). Skin from exposed and control animals was assessed via light microscopy for the following parameters: type, severity, and distribution of histopathological processes; presence and location of fungal hyphae; and presence of fungal conidia. (Luna LG. 1968. Manual of histologic staining methods of the armed forces institute of pathology, 3rd edn. McGraw-Hill, New York, NY.)