Although having five different ways of transmission the vector-borne is theprincipal way of transmission of Chagas disease, which involves insects of the subfamilyTriatominae (Hemiptera: Reduviidae). Nineteen of the 31 species that occur in Mexico areassociated with humans, and all are capable of transmitting the disease. Pyrethroids are theinsecticides recommended for the control of these vectors in Mexico. We determined thesusceptibility to the pyrethroids deltamethrin and permethrin of peridomestic populationsof Triatoma mazzottii Usinger and two populations of Triatoma longipennis Usinger incomparison with a reference strain for each species. Bioassays were performed for thedetermination of the LD50 for both field populations and reference strains. A maximum of27 fold resistance to deltamethrin was observed in T. mazzottii, meanwhile, for permethrin,T. longipennis from Jalisco show the highest value of 3.19 fold. There was significantlyincreased activity of esterases in field populations in comparison with their correspondingreference strain. The results of the search of kdr mutations related to the resistance todeltamethrin and permethrin in the evaluated species show the presence of mutations inthe field populations, as is the case with individuals of T. mazzottii, for which the mutationwas found A943V, and for the two populations of T. longipennis included in this study,we report the presence of the kdr mutation K964R. Evaluation of the various mechanismsinvolved in resistance to pyrethroids in triatomines from Mexico could guide us to the realjustification for insecticide resistance monitoring.