_1773586250 20260315145050000 Editor editor.jddt@gmail.com Universal Journal of Pharmaceutical Research Universal Journal of Pharmaceutical Research Univ J Pharm Res 2456-8058 2831-5235 03 15 2026 Lègba Nazaire Aïzoun Mindégnisèa Habib Tamègnon Seindé Espérance Mèdoatinsa Chèpo Daniel Chougourou Background and aims: Culex quinquefasciatus, an important vector in the transmission of human diseases has developed resistance to commonly used classes of insecticides in populations worldwide in public health. The current study was aimed to investigate on the current insecticide resistance status in Culex quinquefasciatus Say mosquito populations from Mono department in South-western Republic of Benin, West Africa. Methods: Larvae and pupae of Culex quinquefasciatus populations were collected from the breeding sites in Mono department in 2023 during the great rainy season. WHO susceptibility tests were conducted on unfed female mosquitoes aged 2-5 days old. WHO bioassays were performed with impregnated papers of dichlorodiphenyltrichloroethane (DDT) (4%), permethrin (0.75%), deltamethrin (0.05%), fenitrothion (1%) and bendiocarb (0.1%). Results: The results showed Culex quinquefasciatus mosquito populations were resistant to DDT, permethrin, deltamethrin insecticides. There is possible resistance to fenitrothion and bendiocarb. For that, further studies are needed to detect the real resistance status to these products. There is cross-resistance to both pyrethroid and organochlorine insecticides. Conclusion: The physical barrier of Long Lasting Insecticidal Nets (LLINs) which are regularly distributed free by Beninese National Malaria Control Program throughout the entire country to increase coverage of LLINs is still important despite the insecticide resistance observed.                   Peer Review History: Received 2 December 2025;   Reviewed 6 January 2026; Accepted  18 February; Available online 15 March 2026 Academic Editor: Dr. DANIYAN Oluwatoyin Michael, Obafemi Awolowo University, ILE-IFE, Nigeria, toyinpharm@gmail.com Reviewers: Dr. Hatem Sameir Abbas, Al-Azhar University, Egypt, hsam8406@yahoo.com Dr. Kamal Elbssir Mohammed Ali, Hail University KSA, kamalelbssir999@gmail.com 03 15 2026 http://creativecommons.org/licenses/by-nc/4.0 10.22270/ujpr.v11i1.1485 https://ujpronline.com/index.php/journal/article/view/1485 https://ujpronline.com/index.php/journal/article/download/1485/2080 https://ujpronline.com/index.php/journal/article/download/1485/2080 https://ujpronline.com/index.php/journal/article/download/1485/2081 https://ujpronline.com/index.php/journal/article/download/1485/2105