ABSTRACT: Protection of Bojnice natural treatment thermal waters in relationship to the coal exploitation in Novaky Coal Deposit was legislative ordered in the year 1972 by Slovak Republic Government. The protection has come out from hydrogeologic observations of 60-ties years. Next hydrogeological and minig works after the year 1970 have brought new knowledge. There are reviewed older assumes with new observations in the article and within the frame the thermal water protection of wider Horna Nitra Valley region is suggested.