In the paper, the design and method of operation of a robot cell for the assembly of rebar cages for beams and columns is described. The input elements are pre-manufactured rebars, and the output consists of rebar cages. Inside the robot cell, assembly is performed by robots equipped with tools for grasping the rebars, tools for bending the stirrups, and tools for welding the stirrups to the longitudinal bars. Various mechanisms for supplying the robots with rebars and supporting them during the assembly process have also been designed. Because of the specific nature of the assembly process, where robots have to successfully avoid various obstacles, mass-produced robots cannot be used for the assembly of rebar cages. For this reason, special robot configurations have to be designed. The robot cell described in this paper is at present at the design stage. It was modelled and simulated using the program  3 for robot simulation, which makes it possible to study, optimise, and design in detail the proposed robot systems. The figures in the paper describing how such a system works have also been taken from this simulation.