ABSTRACT: The emergence of mineral waters in Baldovce and Sivá Brada is bound to crossing of unsealed fault systems, older of NE - SW direction and transversal younger of NW - SE and N - S directions. They are weakly to medium mineralised, hydrocarbonate, hydrocarbonate - sulphate, calcium magnesium - sodium and calcium - sodium, carbonic waters. The hydrgeological structure Baldovce - Sivá Brada is of the character of a combined hydrogeological structure, which is formed by a semi - closed hydrogeological structure in the lower part, represented by the Krížna nappe and an open hydrogeological structure in the upper part, represented by the Hronicum. The infiltration area of this part of the structure is situated at the boundary of the Branisko Mts., with the Levočské vrchy Mts., which are built up of Mesozoic, crystalline and Paleogene rocks disturbed tectonically.