Efficacy of the bacterium Bacillus sphaericus concentrations as well as starvation, on the symbiont protozoa and survivorship of the ter­mite Cryptotermes brevis was evaluated. The occurred protozoa belong to Calonympha sp., Devescovina spp., Foaina spp., Hexamastix spp. Oxy­monas sp. and Tricercomitus spp., showed highly significant differences after tested treatments. Total mean of the protozoa reached 17626. 67, relative percentages of species to the control varied between 12.71 to 21.63 of Hexamastix spp. and Devescovina spp., respectively. The Tricercomitus spp. was the only protozoa, significantly affected by the-lowest concentration (21x10⁷ v.s./m1), while no significant variation was found between means of other species at the low or intermediate con­centrations 21 x 10⁷, 42x10⁷ and 62.16x10⁷ v.s./rni, respectively. All protozoan species distinctly decreased due to the starvation. Great loss of total protozao was observed at the highest concentration of B.sphaericus (84 x 10⁷ v.s./ml). Significant variation occurred between total protozoan mean after starvation and the highest concentration treatments (1413.33 and 6426.67, respectively), while survivorship of both treatments were relatively similar (82.00 and 84.00%, respective­ly). It could be claimed that decrease in protozoan numbers, may not be the only factor limiting the survivorship of the termites, Pathogenicity of the B.sphaericus would be other critical affecting factor. Intermediate concentration 42x10⁷ and 62.16x10⁷ v.s./m1 gave insignificant varia­tion between their survival percentages. For ideal slow acting termiti­cide, on field application, the higher concentration of the intermediate ones (62.16 x 10⁷ v.s./ml) is preferred to compensate loss of the bac­terium, due to suppression of virulence, diffusion or penetration within wooden surfaces.