Discontinuities and their characteristics play the most important role in the possibility of failure, and their inclination and direction of inclination can form different types of failures. Some of these types of failure are plane, wedge, rotational and rollover failure. This thesis presents the issue of wedge failure, the formation of which requires two intersecting failure planes. We distinguish between two approaches to calculating slope stability, deterministic and probabilistic. As a result, the deterministic approach gives a safety factor that must be greater than or equal to one in order to declare a slope stable, and the parameters in the calculation are unambiguously determined, while this is not the case for the probabilistic approach. The probability of failure with parameters that vary by a certain standard deviation, and with set relative minimum, maximum and mean values is the result of a probabilistic approach. At the end of the work, using the SWedge program from the Rocseince software package, five different cases of the influence of the presence of cohesion, external load, water and earthquakes on slope stability will be presented using probabilistic analysis.