The bachelor thesis is pointing out the issue of building structures and construction assemblies in terms of fire safety. We will show the basic division of the building structures, construction elements and construction assemblies in terms of fire safety in accordance with applicable law. The results of the thesis we will give you some examples of the most commonly used building structurs and their division into appropriate classes, witch are fireproof, mixed, flammable construction assemblies. In the end of the bachelor thesis, we will show the importance of the correct determination of the structural assemblies in terms of fire safety of buildings.