en Biology & physiology Biology & physiology پژوهشي Orginal research papers Chironomidae is one of the most important elements of the aquatic benthos all over the world, which has its own ecological and biological importance in different aspects. The present study has been conducted to investigate the chironomid diversity in Taleghan River in two seasons, spring and summer 2016 for six sampling points (Asfaran, Varkesh, Mir, Jostan, Barikan and Gooran). The sampling procedure was done by applying a simple dredge in five replications for each sampling point. The results have showed that there was a great diversity of Chironomidae in Taleghan River which composed of four sub-families and 21 different genera; Chironominae (<em>Chironomus, </em><em>Robackia, Stenochironomus, Omisus, Cryptochironomus, Saetheria, Cryptotendipes, </em><em>Microtendipes, </em><em>Paratendipes, Constempellina </em>and<em> Neozavrelia</em>), Orthocladiinae (<em>Bryophaenocladius, </em><em>Comptocladius, Echinocladius, Smittia, Botryocladius, </em><em>Symbiocladius, </em><em>Psectrocladius and Gymnometriocnemus</em>), Tanypodinae (unidentified genera in Pentaneurini tribe) and Diamesinae (<em>Potthastia and </em><em>Diamesa</em>). Ten genera have been reported for the first time in Iran. Diversity on abundance of each genus in different months and sampling points might be the result of the environmental conditions and water pollution.<br> &nbsp; Fauna, Chironomidae, Taleghan River, Alborz, Iran 974 985 http://jifro.ir/browse.php?a_code=A-10-2598-1&slc_lang=en&sid=1 H. Houri Parvin haleh.parvin@gmail.com 100319475328460034798 100319475328460034798 No Dep. Biology, Fac. Biological Sciences, Islamic Azad University, Varamin-Pishva Branch S. Yousefi Siahkalroudi siamak.yousefi1@gmail.com 100319475328460034799 100319475328460034799 Yes Associate Prof. N Kheradpir n.kheradpir@gmail.com 100319475328460034800 100319475328460034800 No Assistant Prof.