Background: Pyrethroid resistance in Aedes aegypti is of major concern to the control of several arboviral infections. The major mechanisms of Pyrethroid resistance in mosquitoes are target-site insensitivity and elevation in the activity of detoxification enzymes. In this study, we assessed the susceptibility status of Aedes aegypti population from Lagos to Pyrethroid and the impact of metabolic enzymes on resistance development. Methods: Larvae of Aedes aegypti were collected from differ ent habitats in Lagos Mainland Local Government Area, Lagos state. Adult mosquitoes of 2-5 days were exposed to diagnostic dose of permethrin and Deltamethrin using the CDC method. Synergist assay was done with pre-exposure of samples to PBO before exposure to insecticide. Esterase and GST activities were measured using standard protocol. Regression Probit was used to compute the KDT50 and KDT95. Analysis of variance was used to compare the difference in mean of enzymes activities. Results: Aedes aegypti population from the study location is resistant to permethrin (33% ) and Deltamethrin (80%) within the diagnostic time. PBO pre-exposure increases percentage knockdown from 33% to 82% and 80% to 87% for permethrin and Deltamethrin respectively. The activity of GST was higher (P