Tehran University of Medical Sciences Journal of Arthropod-Borne Diseases 2322-1984 10 4 2016 10 24 483 492 EN Yaser Salim-Abadi Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Mohammad Ali Oshaghi Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Ahmad Ali Enayati School of Public Health and Health Sciences Research Centre, Mazandaran University of Medical Sciences, Sari, Iran Mohammad Reza Abai Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Hassan Vatandoost Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Mohammad Reza Eshraghian Department of Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Hossein Mirhendi Department of Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Ahmad Ali Hanafi-Bojd Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Mohammad Amin Gorouhi Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran AND Department of Environmental Health and Medical Entomology, School of Health, Kerman University of Medical Sciences, Kerman, Iran Fatemeh Rafi Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran 2015 11 24 2015 11 24 Background: During recent years transmission of Dirofilaria immitis (dog heart worm) by Culex pipiens and West Nile virus have been reported from Iran. The present study was preformed for evaluating the susceptibility status of Cx. pipiens collected from capital city of Tehran, Iran. Methods: Four Insecticides including: DDT 4%, Lambdacyhalothrin 0.05%, Deltamethrin 0.05% and Cyfluthrin 0.15 % according to WHO standard  methods were used for evaluating the susceptibility status of Cx. pipiens from Tehran moreover  For comparison susceptibility status a Laboratory strain also was used.  Bioassay data were ana­lyzed using Probit program. The lethal time for 50% and 90% mortality (LT50 and LT90) values were calculated from regression line. Results: The susceptibility status of lab strain of Cx. pipiens revealed that it is susceptible to Lambdacyhalothrin, Deltamethrin, Cyfluthrin and resistant to DDT. Moreover cyfluthrin with LT50=36 seconds and DDT with LT50=3005 seconds had the least and most LT50s. Field population was resistance to all tested insecticides and DDT yielded no mortality. Conclusion: Highly resistance level against all WHO recommended imagicides were detected in field populations. We suggest more biochemical and molecular investigations to detect resistance mechanisms in the field population for further decision of vector control. https://jad.tums.ac.ir/index.php/jad/article/view/331 https://jad.tums.ac.ir/index.php/jad/article/download/331/289