This study shows the morphological identification of anaerobic fungal strains isolated from fecal samples of goats inhabiting Turkey and the effects of various metal ions and chemicals on extracellular xylanase production. Three different anaerobic gut fungi isolated from wild goats in Turkey were identified as Neocallimastix spp. xylanase, cellulase, and lichenase production were tested in culture supernatants, and the maximum-specific activities were found as 560.42 ± 9.39, 159.70 ± 3.88, and 157.36 ± 3.83 (μmol/min/mg protein), respectively. While the optimum temperature range of exoxylanases was found as 40-50°C, their optimum pH range was determined as 6.0-6.5. Xylanase activity decreased in metal ions and other chemical reactants based on dose. The metal ion that significantly inhibited xylanase activity was Fe +3 . It was found that the ferric ions inhibited xylanase activity in all three anaerobic gut fungi by 30%-90% depending on molarity. On