The main objective of our paper was to evaluate the satisfaction of tourists with selected services in the Slovak Karst National Park, in the Domica Cave and in the Ochtinska Aragonite Cave, both of which are on the UNESCO list of natural monuments. Given that these caves are located in the national park, the theoretical introduction deals with the terminology related to sustainable development and subsequently also in the context of sustainable tourism. In total, we addressed 146 respondents and evaluated the obtained data by appropriate mathematical-statistical methods. We found that visitors to the Domica Cave are significantly more satisfied with the information services as well as the infrastructure at this cave, as visitors to the Ochtinská Aragonite Cave. However, visitors to the Ochtinská Aragonite Cave are much more satisfied with the guide service at this cave than visitors to the Domica Cave. The dissatisfaction of the visitors in the case of Domica cave is? caused by the price of souvenirs and the variety of its offer, while the negative response to the Ochtinská Aragonite Cave can be attributed to the quality of the access road, which was reconstructed after the survey in 2019.????????