The role of the ResD-ResE two-component signal transduction system in regulation of the bacilli guanyl-specific ribonucleases genes expression was studied. The proteins with the homology to the Bacillus subtilis ResD and ResE regulatory proteins were found in all sequenced genomes of the Bacillus. Using the B. subtilis strains deficient in the genes for these proteins it was shown that the ResD-ResE signal transduction system positively regulates the expression of the genes for B. intermedius, B. pumilus, and B. thuringiensis ribonucleases in the B. subtilis host cell. The data obtained in this work indicate that regulatory system similar to the B. subtilis ResD-ResE two-component signal transduction system also functions in other representatives of the Bacillus genus.