Rapid urbanization and increasing agricultural activities raises risks of surface water impoundment pollution at the Salt Lake which is one of the most important natural sources in Turkey. The Lake is a hazardous region for surface measurements especially in spring months due to its bottom covered with a 1 to 30 cm. salt layer. It is, therefore, necessary to make water quality assessment using remote sensing data. The applications of remote sensing techniques have been in use over the years for this purpose. In order to evaluate changes, in this paper, the water quality at the Salt Lake was examined by using remote sensing data. Firstly, Landsat (MSS, TM and ETM) and ASTER images were collected for providing multitemporal satellite data. After the image processing operations such as geometric correction, image classification, all resulting data were evaluated together. It is obvious from the remotely sensed and treated data that the water quality has retrogressed during the last two decades due to uncontrolled domestic, agricultural and industrial wastewaters. It is suggested that the waste discharges should be controlled and the surface water pollution monitoring should be carried out using satellite technology in addition to ground measurements.