The main processes of formation of mineral waters of the Republic of Moldova are the exchange reactions, hydrolytic leaching of sedimentary rocks and hydro injection the gas discharge of deep fluids in the aquifer formation system mesocenozoic system through tectonic cracks. Chemical composition of waters is determined by the processes of mixing water of different horizons, for example, Titano-Valanginian (carbon dioxide), apt-albsig (fresh water) and upper Cretaceous (saline relict marine waters). Natural waters are characterized by ionic composition, total mineralization of dissolved carbon dioxide, pH, electrical conductivity and other physical and chemical indicators. On the territory of the Republic of Moldova developed mineral water, the chemical composition of which is close enough to each other by of genetic similarity of geological conditions of their formation. Studies of the chemical composition and physical and chemical properties of natural mineral waters form the basis of their distribution into types, groups and classes, and the conformity to the reference standards of the Eurasian hydro resources. According to the research of mineral waters of the Republic of Moldova are located in a sequential change in the attitude of mole fractions forming their anions (chloride, sulfate, bicarbonate. In the present work it is shown that the natural mineral waters of the Republic of Moldova are a set of water, such as hydro-chloride type (Soroca №1, Varnitsa unique), bicarbonate-sulphate type (Chisinau, Aqualife, Gura Cainarului) sulphate-bicarbonate type (Resan, Cahul, Real, Lider, etc.). The study of the chemical composition by mixing the mineral water with hydro injection unloading in the aquifer formation has shown that: 1. the mixing and/or dilution water mineral waters of the same class does not modify class of water. 2. the mixing of waters of the same group but belonging to different classes, leads to the formation of immiscible solutions; 3. the mixing of waters belonging to different types of waters, leads to the formation of solutions of certain classes of complex groups (chloride-bicarbonate, chloride-sulphate, sulphate and their mixes). The conducted researches have shown that along with the known classification of mineral waters it is possible to identify newly discovered sources of natural waters and their compliance to the reference waters, as well as to organize the monitoring system of the producing fields and quality control of the bottled mineral waters offered for implementation.