ABSTRACT: The Krásnohorská Cave is located in the northern part of the Silická Plateau in the Slovak Karst, southeast of the Krásnohorská Dlhá Lúka village. This fluviokarst cave extends 1,556 m and has an underground stream which penetrates the surface in the Buzgó stream. The cave is known for the Dripstone of Rožňava Caverns with a height of 32.6 m. From 2009 until 2014 we have conducted a chemical and isotope research of the cave’s underground hydrological system and surrounding karst springs. 86 chemical and 62 isotopic analyses were carried out to evaluate the cave system’s karst water. Here, the total dissolved solids (TDS) ranged from 493 to 1,102 mg/L. While calcium and carbonates comprised the dominant water ions, sulphate ions were detected in the inflow in front of the Great Hall. Although most of the water samples belong to the Ca­HCO3 and Ca-Mg-HCO3 water types, Ca-SO4 water was also noted in some places. Chemical composition of water indicates increasing contributions of water from areas built by dolomitic rocks during wet periods. Specific electrical conductivity and chemical composition of water also indicate that one tributary comes from the rocks containing sulphates. Isotopic composition of water showed contribution of snowmelt water in the spring. All waters are isotopically similar.