Salt tolerance was induced in Bacillus subtilis IFO 3025 cells when a moderate osmotic stress was imposed by incubation in the presence of compatible solutes and 0.5 M NaCl or 0.8 M sorbitol. The optimum condition for inducing salt tolerance was observed when the cells were incubated in a solution containing 5 mM glutamate, 2.5 mM KCl, and 0.5 M NaCl or 0.8 M sorbitol. After 60 min incubation, the cells were able to form colonies on an agar plate with high salinity. It was confirmed that the cells acquired salt tolerance by accumulating glutamate and potassium ions in the cytoplasm as the main solute and ion, respectively.