The master’s thesis deals with the analysis and design of a multi-storey steel building for commercial use. A 21.5 m high structure with floor plan dimensions of 32 m x 22 m was analysed. Moment resisting frames form the main load-bearing systems which predominantly carry horizontal loads. The rest of the structure with hinged beam connections to columns forms secondary systems that resist gravity actions primarily. HEM 340 and HEM 300 profiles are used for columns that are change with height. The beams in both directions (longitudinal and transverse) are made of IPE 400 profiles. The composite floor system chosen is Cofraplus 220. All load bearing members are made of S275 steel. Given the type of the structure, a behaviour factor of 4 was assumed and the members were designed for a medium ductility class (DCM). The analysis and design of the structures were carried out in accordance with European norms on a 3D model created with the computer programme SCIA Engineer. The joint design was carried out using the computer programme IDEA StatiCa. All structural members are also manually checked for relevant seismic combinations and fulfil all seismic analysis requirements according to HRN EN 1998. After conducting the seismic analysis of the structure and complying with all the provisions of HRN EN 1998 with the aim of preserving life and limiting structural damage, the steel consumption amounts to 65 kg/m2. Notwithstanding the relatively heavy steel construction, we end up with a lightweight construction with a high degree of ductility, which provides an efficient construction solution, especially if we choose an optimal load-bearing system.