A protease-producing thermophilic bacterium designated Bacillus pumilus JT3 was isolated and identified from a hot spring in Jordan by biochemical tests. The growth and enzyme production in shake flask culture using different operational conditions were studied and observed in a relatively wide temperature range from 25 to 80 C and pH from 6.5 to 13, with an optimal temperature of 60 C and pH 8. The effect of different carbon and nitrogen sources was tested. In addition, the effect of some metal ions on the enzyme stability was investigated showing enhancement with some ions such as Mn2+, Mg2+ and Ca2+ and deactivation with others such as Fe2+, Fe3+ and Zn2+.