Attempts were made to protect Bacillus subtilis, which can be used as a biofertilizer against bacteriophage infection. A bacteriophage resistant mutant of Bacillus subtilis was successfully isolated. Inocula of B. subtilis in forms of free cells, alginate immobilized cells and phage resistant mutant were prepared. Under cultivated soil conditions, inoculation of wheat plants with either immobilized cells or phage resistant mutant of B. subtilis resulted in increase in numbers of spore forming bacteria in the rhizosphere soils and significantly increased plant height (cm), fresh and dry weigh (gram per plant) as compared to plants inoculated with the free cells of B. subtilis. Presence of bacteriophage, in soil cultivated with wheat plants inoculated with free cells of B. subtilis, markedly reduced number of spore forming bacteria in rhizosphere soil and significantly reduced plant height (cm), fresh and dry weight (gram per plant) as compared to plants inoculated with free cells of B. subtilis in absence of phage. In plants inoculated with immobilized cells or phage resistant mutant of B. subtilis, no significant effect for the presence of phage was detected. The phage susceptible cells of B. subtilis and the phage resistant mutant ones were examined by scanning electron microscopy. The scanning electron micrographs indicated that the isolated phage resistant mutant of B. subtilis exhibited slight difference in the dimension of the cells and number of the pili as compared to the susceptible cells.