The thesis presents an evaluation of earthquake resistance of a masonry building made from autoclaved aerated concrete blocks. The investigated family house was built in 1989 and is located in Bloke Plateau. The calculation of design seismic forces by using the method of horizontal forces and the models of strength of masonry walls for sliding shear failure, failure due to formation of diagonal cracks as well as flexural failure, are described in the first part of the thesis. The second part presents seismic analysis of the investigated building. All analyses were done by program ETABS by modelling only ground storey of the building. The basic model consisted of beam/column elements. For comparison, a shell model was also analysed. The calculated internal forces were used to check the resistance of walls independently in the two principal directions of the building. Design seismic forces were determined with consideration of behaviour factor equal to 2 and corresponds to the maximum acceleration from design acceleration spectrum. The seismic demand was compared to the estimated resistance of each wall as well as for the entire building. In addition to the consideration of two structural models, the effects of two different strength classes of walls on the earthquake resistance of the building were estimated due to uncertainty associated with the material properties of the masonry walls. We used the mean strength of autoclaved aerated concrete blocks from literature, which were reduced by a confidence factor. According to the requirements from standards Eurocode 6 and Eurocode 8 results showed that the structure is not able to withstand the resulting seismic loads, since the design value of seismic demand exceeds resistance in multiple walls. More details about the damage of the investigated building could be obtained by using nonlinear methods of analysis. In the case of strong earthquake, the significant damage in the walls is anticipated but it is not likely that the collapse would occur.