This paper summarises available information on water quality associated with post mining lakes of the lignite fields in Greece. In Greece there are three distinctive districts of lignite mining: Ptolemais-Amynteon basin in Northern Greece, Aliveri district in central Greece and Megalopolis in South Greece, Peloponnese. Small lakes have been already formed in some of the remnant voids, while in others the creation of lakes is the main option, after the end of exploitation. Results of various research projects carried out or financed by PPC, concerning the water quality, of the existing and future remnant lakes were used. All remnant lake water is alkaline, due to the alkalinity of geological formations, natural soil and fly ash. The co-dumping of fly ash with mine waste material in the dumping sites improves the absorption of heavy metals and is an unfavourable condition for the dissolution and mobility of heavy metals. Most of them indicate low concentrations or are below detection limits. High values of Mo and Sr are noticed in water of the sumps in Megalopolis and B and Ba in Amynteon, due to their high leaching potential. S content of the lignite is low, usually <1% and even <01%, resulting in relatively low SO4 -2 in remnant lakes. Occurrence of carbonate rocks and calcareous sediments in the basement and in the sediments of the fill of the basins plays also an important role. Surface waters from rivers and streams and unaffected ground waters are of good quality, contributing to the acceptable quality of mine water, according to the environmental limits in South field. In Aliveri, mine water is enriched in sodium. The main conclusion of this study is the significant role of the water – rock interaction on the final lake water quality.