Ercek Lake is a lake characterized with volcanic lava set in ecosystem of Van Lake basin. Lake water contains soda and most important water source is Memedik stream. This study was carried out to determine avifauna of Ercek Lake between June 2000 and June 2004. One observation 0was carried monthly interval using Dobinson method. Total 177 species and 2 subspecies belong to 44 families were detected at the end of the study. The distribution of these species are following according to IUCN Red Data list Categories; 4 species of CR, 11 species of E, 32 species of V, 19 species of NT, 93 species of LC, 6 species of DD and 14 species of NE. 6 observed species were found to be in Globally Threatened category. Observed species were grouped as following; 71 Resident, 71 Migratory, 24 Winter Visitor, 10 Transit Migrant, 2 Transit Migrant-Migrant and 1 Migrant-Winter Visitor.