It is also different to that of East Africa or to that of Ghana . Record of insecticide resistance observed in An. funestus populations so far are mainly caused by metabolic resistance mechanisms either for pyrethroids, carbamates or DDT as neither the L1014F kdr mutation nor the G119S Ace-1 mutation has been detected in this species. Indeed, P450 genes have been found to be associated with pyrethroids resistance and suggested for carbamates as well while mechanisms for the DDT resistance detected in West Africa or East Africa remained uncharacterised. However, the recent detection of the A296S RDLr mutation in the GABA receptor of An. funestus indicates that target site resistance mechanism is also present in this species. Benin is currently scaling up its malaria control program through Long Lasting Impregnated Nets and IRS. It is crucial that information on susceptibility to main insecticides used in public health and the underlying mechanisms being investigated. This will properly inform control programs of the most suitable insecticides to use and facilitate the design of appropriate resistance management strategies. In this study, we report the assessment of the susceptibility of one An. funestus population from South Benin to several insecticides used in public health and also explore the underlying resistance mechanisms. This information will fill the gap in our knowledge on the resistance distribution in An. funestus and help to improve future control programs on this species in Benin. The DDT resistance level observed in this population is not only the highest among the insecticides tested in Pahou, but also is the highest level of DDT resistance MK-1775 Wee1 inhibitor reported for an An. funestus population across Africa until now. No DDT resistance is reported in southern Africa while only a moderate DDT resistance is observed in East Africa. The spread of this DDT resistance to other regions of Africa could reduce the options available for insecticide resistance management of An. funestus populations that are already resistant to pyrethroids and carbamates as seen in southern Africa. However, this scenario is unlikely to happen quickly as it has been shown that there is a restriction of gene flow between An. funestus populations of West and southern Africa. The high DDT resistance in this West Africa population of An. funestus makes it difficult to explain why despite extensive use of DDT resistance has never been observed in southern Africa. We can postulate that this is due to the fact that the molecular mechanism conferring this resistance is completely absent in southern Africa populations and that the restriction in gene flow has not allow it to spread to these populations yet. To confirm this hypothesis, the underlying resistance mechanisms should be fully characterise by identifying the main genes responsible and functionally compare these between the West and southern Africa populations in order to assess differences.