A new, highly inducible fungal promoter derived from the Aspergillus awamori 1,4-β-endoxylanase A (exlA) gene is described. Induction analysis, carried out with the wild-type strain in shake flasks, showed that exlA expression is regulated at the transcriptional level. Using a β-glucuronidase (uidA) reporter strategy, D-xylose was shown to be an efficient inducer of the exlA promoter, whereas sucrose or maltodextrin were not. Upon D-xylose induction, the exlA promoter was threefold more efficient than the frequently used A. niger glucoamylase (glaA) promoter under maltodextrin induction. Detailed induction analyses demonstrated that induction was-dependent on the presence of D-xylose in the medium. Carbon-source-limited chemostat cultures with the uidA reporter strain showed that D-xylose was also a very good inducer in a fermenter, even in the presence of sucrose.