ABSTRACT: In the climatic conditions of the Slovak Republic, the main source of the grou nd water is the precipitation, and mainly the winter precipitation. Also the chemical composition of groundwater is based on the precipitation input. The precipitation chemistry is monitored in longer time series yet. There is also a 10 years record of d180 the cummulated monthly samples of the 8 SHMÚ stations and d180 and dD in the Liptovsky Trnovec. The isotope composition of sulphur in the sulphates dissolved in precipitations were not studied yet in the territory of the Slovak Republic. 18 sampling sites were selected to characterize the main polluted and unpolluted areas of Slovak Republic. In the samples were measured: H, 0, sulphate and chemistry of snowmelt. Based on such figures, we can interpret the origin of the sulphur in the precipitation, and the additional data of the oxygen and deuterium isotopes can trace the origin of the precipitation water.