A new alkaliphilic strain of Microbacterium producing an alkaline protease was isolated from an alkaline soda lake in Ethiopia. High level of protease activity was produced in the presence of glucose and sucrose as carbon sources. The optimum temperature and pH for activity were 65 degrees C and 9.5-11.5 respectively. Above 50 degrees C, Ca2+ was required for enzyme activity and stability. At 55 and 60 degrees C it retained 100 and 85% of its original activity respectively after 1 h incubation. The enzyme was stable over the pH range of 5-12.