Pathogenic Escherichia coli are found in the contaminated raw meat. Contamination is common in Pakistan due to unhygienic condition. The present work was based on the entomopathogenic effect of E.coli against Tribolium castaneum. The cultured sample of E.coli O157 isolated from raw meat was used in this study. Microbial screening of pathogenic bacteria was done by using different media such as TSB, MacConkey and Novobiocin. Rearing of Tribolium castaneum was done in the Laboratory of LCWU. Bioassay technique was applied for the detection of effect of E.coli against the Tribolium castaneum. The Bioassay was applied in triplicates in bioassay glass vials. The results had shown that E.coli did not have any effect against Tribolium castaneum.