The study was carried out in Tathleeth governorate at Aseer region of southwestern Saudi Arabia which is considered the largest district in the region. It lies between    18^o 42' - 20^o 00' N and 34^o 20' - 44^o 30' E. The major habitats of the study area were ecologically described and their snake fauna were surveyed in spring 2015 to summer 2017. The present survey contained a checklist of 92 specimens belonging to 12 species and 6 families. These species were Psammophis schokari, Rhagerhis moilensis, Spalerosophis diadema cliffordi, Platyceps rhodorachis rhodorachis (Colubridae),Cerastes gasperettii, Echis coloratus, Bitis arietanus arietanus (Viperidae), Naja haje arabica,Walterinnesia aegyptia (Elapidae), Eryx jayakari (Boidae), Atractaspis engaddensis (Atractaspididae), and Leptotyphlops macrorhynchus(Leptotyphlopidae). Regarding species richness, Colubridae were represented by 42.8% followed by Viperidae 27.2%, Elapidae (7.7%). Boidae (12%), Atractaspididae (8%) and Leptotyphlopidae (2.2%) and were represented by 3 species with 12 samples in total. This study was suggested to highlight on the diversity of snake's fauna of Tathleeth District, Aseer region, south west of Saudi Arabia, as an important part of the ecosystem that has to be maintained.