Abstract BACKGROUND Temephos is an insecticide widely used in Venezuela to control the proliferation of the larvae of Aedes aegypti (L.), the principal vector of dengue virus. The aim of this study was to identify the susceptibility to temephos of Ae. aegypti in four locations in western Venezuela: Lara, Tres Esquinas, Ureña and Pampanito. Larval bioassays were conducted on samples collected in 2008 and 2010, and the levels of α ‐ and β ‐esterases, mixed‐function oxidases, glutathione‐ S ‐transferase and insensitive acethyl cholinesterase were determined . RESULTS Larval populations from western Venezuela obtained during 2008 and 2010 were found to be susceptible to temephos, with low resistance ratios and without overexpression of enzymes . CONCLUSIONS The low RR values reveal the effectiveness of temephos in controlling the larval populations of Ae. aegypti . Control strategies must be vigorously monitored to maintain the susceptibility to temephos of these populations of Ae. aegypti . © 2013 Society of Chemical Industry