Mosquitoes are important vectors of various diseases, and their control is essential to minimize their impact on human health. Traditional methods of mosquito control have relied on the use of insecticides, which have negative effects on the environment and human health. Biological control has emerged as an effective alternative and nuclear polyhedrosis virus (NPV) has shown potential as a biocontrol agent against mosquito populations. This study aimed to investigate changes in vitellogenin (Vg) gene expression and protein profiles in female Culex pipiens mosquitoes treated, in the larval stage, with nucleopolyhedrovirus (NPV) before and after blood feeding. Real-time quantitative PCR was used to measure Vg gene expression. In the untreated females, the Vg gene expression increased in the 24 hrs post-blood meal (pbm) then decreased at 48 hrs pbm while in the treated females, the level of Vg gene expression declined in both 24 & 48 hrs pbm. SDS-PAGE analysis of ovary homogenates revealed differences in protein composition between normal and treated blood-fed females, with a range of molecular weights observed in the blood-feeding stages in 24 to 48 hrs pbm. The study concludes that NPV treatment significantly reduces Vg gene expression and protein profiles in Cx. pipiens mosquitoes. Our research emphasizes the possible application of NPV to control mosquito populations effectively, and further research on the mechanism underlying the pathogenicity of NPV and its effect on vitellogenesis in adult females could open new avenues for mosquito control.