To obtain a better understanding of the olfactory processes that allow mosquitoes to identify human hosts, a molecular study has been performed to identify and characterize molecules in the olfactory signalling pathway of the African malaria vector Anopheles gambiae. Using cDNA libraries from antennae of females and males, a collection of cDNAs encoding odorant binding proteins and other novel antennal proteins were isolated and characterized, which represent various families of putative carrier proteins with homologues in other insects. Using filter array hybridizations and quantitative RT PCR, regulation and gender specificity of expression of these genes was investigated. Significant differences in steady-state levels of some of these putative carrier protein genes were detected between the sexes and after blood feeding in females.