Basic knowledge of population status is effective for the conservation of many species, especially threatened and endangered species. In this study, we used the Mark-recapture technique (Linconln-Petersen method) as an established method for estimating population in wildlife surveys. Population surveys of critically endangered newts conducted for Neurergus derjugini in the streams of Kurdistan and Kermanshah Provinces, western Iran, at Sarvabad, Marivan, Baneh, Saghez and Nosoud. The study consists of estimating population size by sampling annually for two consecutive years (2018-2019) with each annual sampling consisting of several surveys between May-August. The species has a restricted distribution, occurring at high mountain streams. Our results also reject the occurrence of this species in Sarvabad and Awraman stream habitats and water ecosystems as was stated by former researchers. Distribution information of this species was updated in the region, and all known records are mapped. The results showed that Miri Sour (Marivan) with 1591-1568 and Asnabad (Marivan) with 14-18 specimens as estimated populations were found as most and less populated and suitable habitats respectively.