Analysis of the stability conditions of rock masses in underground karst systems involves a study of the breakdown processes that acted during the formation of the caves, integrated with a survey of the present conditions of the walls and roof. Especially in show caves, and in caves frequently visited by speleologists and researchers, evaluating the susceptibility related to rock falls is of paramount importance. In this contribution we presents the results of a research carried out at the Castellana-Grotte show caves (Apulia, southern Italy), where we performed a geomechanical characterization of the carbonate rock mass, aimed at obtaining the necessary data for up-to-come stability analysis.