Open-pit mines have significant adverse water quality impacts and end pit lakes formed from abandoned open-pit coal mines have commonly environmental problems. Determining and monitoring of the chemical water characteristics of end pit lakes are very important and play a key role in understanding the anthropogenic impact. The purpose of this study was to determine the amount of different macro-elements (potassium (K), calcium (Ca), sodium (Na), magnesium (Mg), phosphorus (P)), heavy metals (iron (Fe), aluminum (Al), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn)), and different water parameters (acidity (pH), electrical conductivity (EC), temperature (degrees C), and dissolved oxygen (O-2)) in 11 end pit lakes formed after coal mining operations in Agacli-Istanbul, Turkey. All investigated characteristics in lake waters showed significant differences in temporal and between lakes. When the relationships between element concentrations and other parameters (pH, EC, degrees C, and O-2) were examined, pH emerged as the most effective factor has a wide range, and has a negative correlation with P, Ca, Mg, Fe, Al, Cu, Ni, Zn, and Mn. The EC in the lake waters was positively correlated with the changes of Ca, Mg, K, and P, while it showed a negative correlation with Na concentration. Besides, dissolved O-2 content was positively related to Fe and Cu and negatively related to water temperature change. Results showed that monitoring the water characteristics of end pit lakes is essential indicating the major concern with water pH. The results on water parameters may be a valuable basis for the preparation of management plans of the post-mining landscape.