A gene library of the thermophilic bacterium Bacillus stearothermophilus was made in a plasmid vector, and the gene of thermostable metalloproteinase was cloned. Restriction mapping proved it to be close to the B. stearothermophilus metalloproteinase T gene cloned earlier. The cloned expressed in B. subtilis, and its protein product was characterized in terms of heat stability and temperature optimum.