AeSCP-2 a sterol carrier protein is involved in sterol trafficking in mosquitoes. The activity of AeSCP-2 gene is important for the development of the mosquito. Results from earlier studies indicated that transcription of AeSCP-2 is up-regulated by 20-hydroxyecdysone in tissue cultures. Upstream promoter sequence of the AeSCP-2 gene was ligated to a reporter gene and the promoter activity was analyzed in transfected Ae. aegypti Aag-2 cells. At 5x10-6M concentration, 20-hydroxyecdysone elevated the AeSCP-2 promoter activity significantly. The results imply that ecdysteroids may be involved in the regulation of AeSCP-2 gene expression at the transcription level.