The topic of this thesis is the assessment of seismic resistance of an existing masonry building. The residential building is located: Deželićeva 29., 10 000 Zagreb. The masonry building was damaged by a series of earthquakes that occurred on March 22, 2020. further and the rehabilitation of the building is planned. A 3D laser image of the existing condition of the building was made for the building in order to determine the geometry and damage caused by the earthquake. Also, the laser image determines the load-bearing walls, their deviations in verticality, eccentricity, and continuity to the foundation. Based on the analysis of the existing situation, a numerical model was developed and static and dynamic analysis of the structure on the effect of earthquakes was performed. First, a model of the structure for the undamaged condition before the earthquake is made and analyzed. From such a model, the correspondence with the actual condition of the cracks to which the building provided a response to the recent earthquakes is examined. In order to take into account certain influences, assumptions have been introduced in the model that describes in more detail the crack state of the structure and the reduced mechanical characteristics of the material. After calibration of the model in relation to the actual state, it approaches the analysis of the numerical model of the structure on the level of its seismic resistance. Based on the conclusions of the analysis of the existing condition, the guidelines for reconstruction within level 2 are presented. The final part of the paper consists of graphic contributions to the geometry of the existing condition by floors.