This study was conducted in four strains of Aedes aegypti mosquitoes to evaluate the enzymatic activity profiles in the city of Mossoró, Rio Grande do Norte, and correlate them with biochemical mechanisms of resistance to insecticides. Mosquitos were used to quantify the following detoxification enzymes: Mixed-Function Oxidase (MFO), PNPA-esterase (PNPA-EST), and Acetylcholinesterase (AChE). The profiles were compared statistically with profiles from the Rockefeller strain, through the Kruskal-Wallis test and Dunn's multiple comparisons (p < 0.05). The 99 percentile of the values of enzyme activity from the reference strain was calculated for each enzyme, and the percentage of individuals above the 99 percentile was quantified. The enzyme activities were classified as "Unchanged" (< 15%), "Identified change" (> 15% and < 50%), and "Substantially changed" (> 50%). The statistical analysis revealed significant differences in the MFO and AChE profiles, which are fundamental in the determination of profiles of resistance to insecticides. Three populations were classified as "Substantially changed" for MFO. The altered enzymatic activity showed that the changes could have an important role in exposing resistance to insecticides.