Background:Polluted indoor environments pose health challenges such as allergy, infections, and toxicity. Most indoor air pollution comes from hazardous non-biological and biological agents. Due to the nature of the indoor environment of libraries, it is prone to colonization by fungal species. Method:Three sampling sites were used for the study and they include Festus Aghagbo Nwako Library, Main campus Awka, Medical Library, Nnewi Campus and Library Complex, Agulu campus. A total of 100 air samples were analyzed Using the Zefon A6 Single-stage microbial air sampler and Malt Extract Agar supplemented with 0.05mg/ml of chloramphenicol while 16 nasal swabs were collected from the staff present using sterile swab sticks. The mould isolates were identified using the slide culture technique while the yeast isolates were subjected to candida chrom agar and integral yeast plus identification. Antifungal susceptibility was performed using the integral yeast plus system and the agar well diffusion technique. Results:Out of the 100 air samples, a total of 625 fungal isolates were identified of whichC.lunata201 (32.16%) was the most predominant, whileP. marneffi, P. expansum, A. restrictus, A. infectoriaandR. rubra1(0.16%) occurred the least. All significant at (p≤0.01).A total of 7 fungal spores were isolated from the 16 nasal swabs and appeared thus in descending order of frequency:P. notatum, 3 (42.85%),A. niger, C. lunata, C. albicansandF. aqueductum, 1(14.3%). Antifungal Susceptibility of the 28 yeast isolates indicated thatC. famata, C. laurentiiandC. luteolus, were all susceptible to commonly used antifungals in the integral yeast plus system with a 100% susceptibility value, while the mould isolates showed relatively moderate susceptibility to selected antifungals. Conclusion:The organisms isolated are well known to be pathogenic especially to immunocompromised individuals. Their presence in the indoor environment of libraries serves as a risk factor to both the library staff and visitors. Adequate precautionary measures and occasional environmental surveillance need to be inculcated in order to reduce the number of fungi in the indoor environment of these libraries.