Background: Musca domestica is a cosmopolitan public health and agricultural pest that is known to be a carrier of multiple pathogens and cause economic losses in production of animals. Objective: The current research paper examined Bacillus sphaericus isolates as Larvicidal agents in larvae of M. domestica as a third instar organism under controlled laboratory environments. Methodology: There were five concentrations of B. sphaericus spores (1×10⁴ - 1×108 spores/ml), positive (Bacillus thuringiensis israelensis) and negative (sterile water) controls, and 600 larvae in total. Results: Larval death mortality was observed to take place at 24, 48, and 72 hr within the treatment period and was corrected by Abbott and probability analysis, ANOVA. Findings showed definite dose-dependent effect. At 72 hr, mortality was 20% at 1×10⁴ spores/ml to 95% spores/ml 1×108 to the negative control of 4% mortality. Positive control group mortality after 72 hr was 92%. The LC50 and LC90 were estimated to be 3.2×106 and 1.1×107 spores/ml respectively by Probit. Significant changes among treatments were established with statistical tests (F= 46.3, p<0.001). Conclusion: B. sphaericus has high larvicidal activity against M. domestica and this is similar to commercial reference strains. The study presumes that B. sphaericus can serve as a safe biocontrol agent that is environmentally friendly and could help eliminate the usage of chemical pesticide and may be included in an integrated pest management program.