Water and sediment chemical compositions were investigated in 75 post-mining lakes in the eastern part of the Muskau Arch region (Western Poland, Central Europe). The lakes, originating from lignite and clay surfaces and underground mining activity, exhibited a wide gradient of physical and chemical water parameters. The most pronounced variability in water parameters was observed in pH values, conductivity, and oxygen concentration in the mixolimnion and monimolimnion. In addition, the lakes varied in terms of their trophic status, indicated by their dissolved organic carbon (DOC) and phosphorous concentrations. In general, lakes with higher pH values had higher trophic states, and some even exhibited hypertrophic conditions. The Monte Carlo test indicated that the water pH, phosphorus, DOC, and silicon concentrations could significantly explain the chemical characteristics of sediments.