The diverse habitats and diets encountered during the life cycle of an Anopheles mosquito have necessitated the development of extensive families of detoxification enzymes. Expansion of the three detoxification enzyme families (cytochrome P450s, carboxylesterases and glutathione transfereases), has occurred in mosquitoes compared with Drosophila, however, very little is known regarding the developmental expression of theses genes. Using a custom made microarray we determined the expression profile of the detoxification genes in adults, larvae and pupae of the malaria vector A. gambiae. The expression of approximately one quarter of these genes was developmentally regulated. The expression profile of each of these genes and the information this data provides on putative functions of the mosquito detoxification enzymes is discussed.