Paecilomycesvarioti produced an extracellular xylanase and B-xylosidase when cultured in a medium containing xylan and corn steep liquor. Xylose (2%, w/v) totally inhibited production of both enzymes. The enzymes were purified and both had a pH optimum of 4.0. The xylanase had a molecular weight of 20,000, an isoelectric point of 5.2 and was inactive on all substrates tested except xylan. The β-xylosidase, a glycoprotein, had a molecular weight of 67,000, an isoelectric point of 4.0 and had highest activity on p-nitrophenyl-β-D-xyloside. The xylanase had a Km of 49.5 mg/ml for xylan and the β-xylosidase had a Km of 5.4 mM for p-nitrophenyl-β-D-xyloside.