We present the description of Chironomidae (Diptera) collected from Sirwan River watershed in Kurdistan province of Iran. This study is part of a larger monitoring program conducted from 2017 to 2018, surveying the freshwater flora and fauna of this watershed. Over half of the benthic invertebrates collected in this monitoring were Chironomidae, presenting the most diverse group. A total of 35 species of Chironomidae were found in Sirwan River Watershed of which 18 representing new faunistic records for Iran, range extensions for the Palearctic, and three being likely new species. Sirwan River is the largest running water habitat in the province of Kurdistan and an important resource for the local and regional economy. These studies help identify the organisms of freshwater ecosystems and provide useful tools for investigators, making better assessments of water conditions and improving their management.
