A seismic analysis of precast reinforced concrete building is presented in this graduation thesis. The main objective was to estimate the impact of concrete infills on seismic response of structure. In the first part of thesis the principles and analytical procedures for modelling of such structures are described. The effect of concrete infills was taken into account with a single-strut model. The modelling of structure and all the analysis were according to Eurocode 8 performed by software ETABS v9.7.4. For comparison, two different models were developed. The first one is a model which accounts for the effect of concrete infill, whereas the second model consisted of bare frame, which is often used in practice. It was found that infills reduced storey drift for approximately 38%. There are some differences in bending moments, too. In the case, where the infill which having the height much smaller than the height of column, connects to column, bending moments were observed for 43% greater in comparison to those based on the bare frame. However, much greater difference was observed for the shear forces in the columns, which were around five times greater than that observed in the case of bare frame.