The invention concerns a rotor arrangement for an electrical drive motor of a compressor, particularly a refrigerant compressor, with a rotor having a rotor lamination of stacked sheet plates, and a shaft, which is inserted in an axial recess of the rotor lamination and is unrotatably connected with the rotor lamination, the recess being formed by openings in adjacent sheet plates. It is endeavoured to simplify the manufacturing of such rotor arrangements. For this purpose, it is ensured that openings of different sizes are provided in the sheet plates, at least two sheet plates forming a first group, each having an opening, which is smaller than the cross-section of the shaft, the remaining sheet plates forming a second group, each having an opening, which is larger than the cross-section of the shaft.