This graduation thesis presents a simplified seismic performance assessment of the building of the Faculty of Civil and Geodetic Engineering building of the University of Ljubljana, constructed in 1969. The building's geometry and material characteristics were taken from previous studies. A simplified seismic performance assessment of the building was carried out by the N2 method, which is part of the Eurocode 8 standard, but the pushover curve was replaced by the simplified pushover curve defined by the initial stiffness or the fundamental period, strength and deformation capacity of an analysed building. The initial stiffness and the fundamental building period were determined on the basis of the three-dimensional numerical model of the structure. The strength of the building was estimated according to the minimum load-carrying capacity of a Japanese guidebook, while the deformation capacity of the structure was estimated on the basis of nonlinear limit-state displacements of critical elements of the critical storey, which were calculated with by the equation in closed-form. For both the longitudinal and transverse directions, large wall cores of the first storey proved to be the critical elements of the structure. The seismic performance of the building, expresses in terms of peak ground acceleration, is significantly dependent on the fundamental period of the building. The peak ground acceleration causing exceedance of the near-collapse limit state amounted to 0.40 g and 0.23 g in the longitudinal and transverse directions, respectively. The estimated seismic performance of the building is lower than that in a previous study based on a conventional pushover by 25,4 % and 8,0 %, respectively, for the longitudinal and transverse direction of the building. A smaller difference was observed for the case without further reduction of the fundamental building period due to the effect of the idealisation of the pushover curve.