The cellobiose phosphorylase gene of Cellvibrio gilvus was cloned and sequenced. The gene had a high GC content of 70.6% and encoded a protein with 822 amino acid residues. It was expressed in Escherichia coli JM 109 to yield the active enzyme. Based on the N-terminal amino acid sequence of the native enzyme, it is found that the enzyme is produced without a signal peptide. Only two previously reported enzymes showed significant amino acid sequence homology; cellobiose phosphorylase of Clostridium stercorarium (61.4%), and cellodextrin phosphorylase also of C. stercorarium (38.2%).