Sex-specific expression of transgenes in pest insects enables novel genetic control strategies, based either on genetic sexing or the spread of transgenes through the germ-line, to be developed and then tested for implementation. We describe the isolation of the β tubulin genes from the yellow fever mosquito, Aedes aegypti, and the identification of the particular β2 tubulin gene which has expression confined to the testes. We demonstrate that the β2 tubulin promoter of Ae. aegypti can direct the expression of a DsRed genetic marker in the testes and show that labelled sperm can be detected in inseminated spermathecae. The applications for this technology in the genetic control of Ae. aegypti are discussed.