ABSTRACT1. The limnological characteristics of Salda Lake, a deep, soda and highly alkaline lake in the Lake District of southwestern Turkey, are presented.2. Physical and chemical variables indicate that the lake is composed of hydrochemically different water layers formed by groundwater sources located on the floor of the lake.3. Phytoplankton and zooplankton are characterized by a limited number of species and low dominance reflecting the extreme conditions of the lake.4. Hydromagnesite stromatolites occur all around the lake margins. 5. The lake is threatened by falling water levels and organic pollution. Recommendations for the conservation of the lake are presented.