Lakes are sometimes subjected to wastewater discharges originating from different sources. Chemicals such as nitrogen, phosphorus and carbon in certain concentrations might distort and disrupt aquatic ecosystems. Eutrophication of inland bodies of water has become synonymous with the deterioration of water quality, which interferes with most of its beneficial uses. This study, purposing to determine water quality characteristics of Yarseli Lake, located in Antakya, Hatay, began in April 2003 and was carried out for 12 months by taking monthly water samples from two different stations. Water quality parameters of pH, dissolved oxygen, temperature, salinity, chemical oxygen demand (COD), total alkalinity and hardness, ammonia, nitrite, nitrate, phosphate, sulphite, sulphate, chloride, potassium, sodium and silica analyses were done. Changes in water quality parameters of Yarseli Lake by months were determined. This study indicates that Yarseli Lake has not reached the eutrophic stage yet.