Abstract: The present invention refers to a process for mounting permanent magnets in electric motor rotors and is destined, more specifically, to hermetic motor-compressor, which was conceived and developed to provide greater reliability to the assembly, since it is a technical solution capable of absorbing, more appropriately, the dimensional variations of the components involved and allows the use of high speed motor. Said process comprises the following steps: to construct a helical elastic element (6) with a diameter smaller than the outer diameter of the magnet (3) assembly positioned on the outer surface of the metal core (2); to elastically expand the helical elastic element (6); and to engage the helical elastic element (6) around the magnet (3) assembly to enable that the elastic force of the a helical elastic element (6) causes the latter be rigidly molded to the outer diameter of the magnet assembly (3).