The biochemical effects of twoentomopathogenic fungi, Beauveriabassiana and Metarhiziumanisopliae,were studied in the 3rdinstar larvae of Culex pipiens in the laboratory. Results revealed significantreduction in the total proteins of the treated larvae compared to the controllarvae. Thebiochemical studies using (SDS-PAGE) revealed that there was a reduction in thenumber of protein bands due to the treatment with either of the two fungi. The obtained results indicated that the applicationof entomofungi as larvicidal agents against mosquito larvae caused significantchanges in the total protein profile of Cx. pipiens larvae suggesting thattoxins secreted by these pathogens caused damage to the larval proteins whichfinally leads to larval death. Theconclusion is that the fungal pathogens are important as natural biologicalcontrol agents of manyinsect and other arthropods and frequently cause epizootics that significantlyreduce host population. This study recommends the use of B.bassianaand M.anisopliae as biological control agents to the control of Cx.pipiens larvae in order tosuppress this medical vector for publichealth.