The mounting screw (100) for fastening fitting parts, in particular hinge parts to multiple-chamber profiles, having a threaded part which comprises an external thread and is of a length which is greater than the spacing of two adjacent walls of the multiple-chamber profile, comprises a front part (1), as viewed in the screwing-in direction, which comprises a thread (3) and is preferably manufactured from a metallic material, and a rear part (2) which is made from a thermally insulating material, for example plastic.