Burdur Lake is a closed-basin, alkaline, saline lake, at 845 m above sea level in south-west Anatolia, Turkey, divided between the provinces of Burdur to the south and Isparta to the north. It is 30 km long by up to 7 km wide and lies tectonic depression with a maximum depth of 110 m. It is the sixth largest lake of Turkey with an area of 250 km2. It is also an important wetland site for many bird species and is designated a Ramsar Site and have experienced a severe decline in water levels in recent decades. This study aimed to investigate coastline changes of lake and identify the causes for the decline in lake levels. Seven Landsat images from different times, monthly temperature, precipitation, discharge, lake level records and population data were used to analyze these changes. From the results of the image analysis, the levels of the Burdur Lake fell dramatically and shrunk in area from 1975 to 2010. The water surface areas of the Burdur Lake also decreased from 209,01 to 143,80 km2 and a loss of 64.5% over the 35-year period, respectively. The surface area of the Burdur Lake shrunk from 209,61 km 2 in 1975 to 206,49 km 2 in 1984, 200,46 km 2 in 1988, 162,85 km2 in 1998, 153,33 km2 in 2001, 155,73 km2 in 2003, 143,80 km2 in 2010. From 1975 to 2010, the Burdur Lake level declined by 11.86 m from 856.89 m to 845.03 based on ground lake level data. Population growth, rising water consumption for agricultural and domestic purposes and building dams has led to lake levels declining.