Final thesis deals with the design of a floor structure in an object of an operational building, which is designed as a reinforced concrete two-way slab. Thesis consists of three parts. The first part includes technical report, giving an overviw of the structure, its load-bearing system, foundations, surface tretment, environmental impact and fire protection. In the second part, a detailed structural analysis is presented, which includes desig of the beam and slab dimensions, loads calculation, armature design, shear resistance calculation and deflecion calculation. The third part consists of the plan of the slab, upper armature plan and lower armature plan.