A methodology for determining the probability of failure of a curvilinear retaining wall against shear using the Monte Carlo statistical testing method was developed in this paper. An algorithm and computer program implementing this approach are proposed, as well as an example of curvilinear wall calculation is performed together with reliability indices for three design cases are obtained. By under-standing the values of the probability of failure in a given case according to one of the criteria, it is possible to determine the risk level of the project and, if necessary, to make changes in the design of the retaining wall. The concept of reliability management in the Eurocode is manifested here in the timely correction of the decisions taken, while it is necessary to use the procedure of quantitative assessment of the probability of occurrence of a particular limit state. The qualitative assessment only indicates the boundaries of the area that roughly characterises the consequences of changes in the geotechnical situation.