Nowadays, according to social and functional needs, various types of multi-storey or high rise buildings are the mostly useable buildings in many towns and cities. Among them, some buildings are constructed as soft storey because of the space occupancy considerations. The soft storey has one level that is considerably greater flexible than the storey above and below it. This type of building has no masonry wall in this level or it can also have a greater height than the rest of the floors. Generally, the soft storey usually exists at the ground floor level but it can form any level of a high-rise building to fulfill necessity. In this study, analysis and design of superstructure for twelve-storey reinforced concrete building are presented. Analysis and design of superstructure of the selected building are carried out by using Extended Three Dimensional Analysis of Building Systems software. Firstly, the model is analysed by using software. For the superstructure, storey drift limitation, P-? effect, overturning, storey shear and torsional irregularities are carried out from design results. Secondly, the structural designs are made by change of storey height and without change of structural element size, seismic zone, exposure type and soil type. Finally, storey drift of all storey levels and the analysis results of structural performance are compared.