In the paper the impact of scaling rules on the performance of a cyclone separator working with a CFB boiler has been investigated. The analysis has been performed with using five sets of scaling relationships and the model proposed by Muschelknautz for calculation of the total and the grade separation efficiency of a cyclone. As follows from the obtained results both the set of scaling relationships as well as the scale of a cold model have an impact on the total grade separation efficiency of a cyclone separator. However, owing to the high total separation efficiency values calculated for all analyzed sets of scaling relationships there is no need to introduce into sets of scaling rules additional formulas typically used for scaling cyclones. This conclusion is of special importance in the case of scaling experiments carried out based on the simplified set of scaling relationships for which a scale of a cold model can be assumed at an arbitrary level.