The topis of this thesis is the assesment of the existing state of the masonry building using dynamic measurement. Precisely, it is a building in the center of Zagreb at the adress Vjenceslava Novaka 7 that was damaged in the earthquake. The project was taken over from the archive of company „SLF projekt d.o.o.“ which deals with designing, supervision and expertise. With their consent and agreement, the existing building was measured and the numerical model was created in the „SCIA Engineer 21.1.“ softver. In the purpose of creating an evaluation report of the existing condition of the masonry structure, the engineers in the mentioned company performed a detailed inspection of the stucture and carried out some of investigative work. Also, a numerical model was created in softver „3Muri“. All documentation related to the project was intoduces and used to compare the obrained results. At the beggining of the thesis are described some of the methods of testing masonry buildings and the structural elements of the building with associated dimensions. The central part of the paper inludes a more detailed description of the performed dynamic measurement, and an evaluation of the results according to the criterion of orthogonality (MAC factor). The basic requirements for load bearing walls were also checked according to the HRN EN 1998-1:2011/NA:2011/A1 standard. Furthermore, the basic dynamic parameters of the structure obtained by testing and the corresponding modal shapes are given. In order to determine as accurately as possible the condition of structure, a numerical model was created that was adjusted based on the dynamic parameteres obtained by experimental testing. Due to unknown parameters, mechanical characteristics of the material and unknown boundry conditions, several model with different wariations were made. An initial model was create on which the improvement of the model was carried out by changing the modulus of elasticity of the brick and replacing the partition walls with the corresponding line load. On one of the mentioned models, significant cracks were inroduced in the construction within the limits that cover the frequencies obtained by experimental testing. A comaprison was also made with the results obtained by the engineers in the SLF project. In the last chapter the topic of contrustion rehabilitation is initiated. An analysis of the dynamic parameters before and after the rehabilitation is presented that is the verification of the increased stiffness of the structure with addes reiforcements. In conclusion is given an opinion on the existing state of the structure based on the measured result in combination with the performed numerical analysis.