ABSTRACT: Prototype of monitoring device, in 5-minutes interval recording groundwater quality parameters in the Buzgó karstic spring was installed in the area of the Krásnohorská Dlhá Lúka municipality. The monitoring device consisted of an optical system, laser system, multi-parameter probe, control unit and datalogger, as well as with wireless data transmission and warning equipment. Turbidity, temperature and specific electric conductivity of water, chemical consumption of oxygen, total organic carbon, dissolved nitrates, numbers of suspended particles in size categories of ≤ 0.9 μm, 0.9 – 1.5 μm and 1.5 – 2.5 μm were continuously measured. To correlate the monitored parameters and microbiological parameters of the spring water, 65 water samples were for microbiological analysis including the presence of coliforms, Escherichia coli, enterococci and microorganisms cultivable at 22 °C and 36 °C. The key moment in comparison of the above parameters seemed to be the functionality of the monitoring device itself. It gradually went through several calibrations until the recorded data gradually approached realistic values. Thus, comparison of sampling results and of monitored parameters only indicates some correlation between coliforms, suspended particles ≤ 0.9 μm and TOC. Presence of Escherichia coli slightly corresponded to turbidity and enterococci with 1.5 – 2.5 μm suspended particles.