The present invention relates to a backing pad (1) with slots for sanding discs with multiple holes, comprising three parts, upper, intermediate and lower, joined together by a fastening system in which the upper part (2), with a frustoconical shape, includes suction holes (7) and a central hole (8), characterized in that the intermediate part (3) comprises suction slots (5), a central hole (8') and in the rear face some suction channels (6) bordered by upraised walls (10); and the lower part (4), with a frustoconical shape, and in which the intermediate part (3) will engage, comprises slots (5) and a central hole (8''), and some suction slots (11) which are arranged in rings, concentric and equidistant between them, and the size of each of the slots (11) increases from the centre to the periphery.