We studied the structure and the abundance of waterbirds assemblages in an arid region of southeastern Algeria for the first time. The results which were obtained from monthly counts for four years from 2013 to 2016 at Fountains of gazelles reservoir, showed 09 species of Anatidae. Three species are sedentary Mallard Anas platyrhynchos, Ruddy shelduck Tadorna ferruginea and Shelduck Tadorna tadorna. Others are wintering birds Northen Shoveler Anas clypeata, Northen pintail Anas acuta, Eurasian Wigeon Anas penelope, Common Teal Anas crecca, Marbled teal Marmaronetta angustirostris, and Garganey Anas querquedula. Both the Common Teal Anas crecca and Northen Shoveler Anas clypeata were highly dominant species accounting for more than 60% of Anatidae. This reservoir has an important role in the preservation of the Anatidea population.