Investigation showed that Aedes albopictus (Skuse, 1894) of Chidambaram-Town, Annamalai-Nagar and Muthiah-Nagar of Tamil Nadu are still susceptible to the insecticide organophosphorus temephos with 98–100 mortality percentages. The resistance ratios of all the three sentinel sites are negligible. LC50 value was 0.002 - 0.003 ppm with high significance. It was the first temephos bioassay case study conducted on DENV vector Ae. albopictus in the selected sentinel sites and estimated lethal concentrations.