Objective To determine the resistance of adult Culex quinquefasciatus and Musca domestica to commonly used insecticides in Dazhu District of Chongqing in 2023， and provide scientific evidence for rational use of hygienic insecticides.

Methods Drug resistance was determined by using adult mosquito contact tube method and adult fly drop method.

Results In 2023， the 24-hour mortality rate of adult Culex quinquefasciatus in Dazu District， Chongqing， against permethrin （0.25%）， beta-cypermethrin （0.025%）， deltamethrin （0.025%）， malathion （5%） and propoxur （0.1%） was 37.35%， 21.92%， 28.33%， 96.43%， and 95.38%， respectively. The median lethal dose （LD₅₀） value of female adult Musca domestica against beta-cypermethrin （95.8%）， chlorpyrifos （97%）， deltamethrin （90%） and dichlorvos （95%） was 2.572 μg， 0.329 μg， 0.406 μg， and 0.492 μg， respectively， with resistance of 829.68， 7.65， 53.42， and 46.42 folds to the above tested insecticides．

Conclusion Adult Culex quinquefasciatus and Musca domestica in Dazu District show various degrees of resistance to commonly used insecticides. It warrants suspending the insecticides with high resistance， whereas mixedly and alternatively administering the insecticides with possible resistance and low resistance. Additionally， we should continue to monitor the resistance and guide the rational use of insecticides.