The cmc2 gene, coding for an endoglucanase 2 (CMC2) of Aspergillus aculeatus, was cloned using both genomic and cDNA libraries, and sequenced. The gene consists of 1230 bp encoding a protein of 410 amino acid residues with a molecular mass of 43,697 Da. The CMC2, composed of an N-terminal catalytic domain belonging to the family 5 of glycosyl hydrolases and a C-terminal cellulose-binding domain (CBD) belonging to the family I of CBDs, showed identity with other fungal endoglucanases, particularly with that of A. niger, A. nidulans, A. kawachii and A. aculeatus. The transcription of the cmc2 gene in A. aculeatus cells that were grown on different carbon sources was measured. Analysis by the ribonuclease protection assay revealed that expression of the cmc2 gene is induced by cellulose and some disaccharides and repressed by glucose.