ABSTRACT: Interaction of surface water bodies with groundwater becomes an important issue of evaluation in terms of EU water framework directive implementation. In order to acquire detailed information on such an interaction in the area around southern margins of the Plešivecká planina karstic plateau (Slovenský kras Mts.), longitudinal profile measurement of specific electric conductivity (resistivimetry) and water temperature (thermometry) were performed along the Štítnik and Slaná River surface flowsand together 18,300 meters long rivercourse sections were covered. While the Štítnik surface flow on the western margin of the karstic plateau was found practically without hidden inflows as very probably losing river, frequently occurring anomalies along both banks of Slaná are typical for the gaining river, at least in this river segment. Interesting feature was observed on the Štítnik River, where a hidden inflow anomaly was detected on the opposite riverbank than a major karstic spring was situated. Using thermometry and resistivimetry in the described way, only position of water interaction points can be detected, while the quantitative aspect can be defined only by flow accretion survey – discharge measurements on appropriately distanced locations of streams. Optimally, both methods should be applied in the same moment at the same place.