A xylanase gene, xynA which encodes xylanase I of Aeromonas caviae ME-1, was cloned in Escherichia coli. xynA gene has a 633 bp open reading frame (encoding 211 amino acid residues) which includes a signal peptide (28 amino acid residues). E coli JM109 transformant produced 0.7 U/ml xylanase, about 80% of which was secreted into the culture medium as mature enzyme. The deduced amino acid sequence shows 79.3, 78.9, and 47.1% identity to family G xylanases of Bacillus subtilis, Bacillus pumilus and Bacillus circulans, respectively.