A disc for a disc brake of the ventilated type comprising a braking band (2) defined by two plates (3, 4), which are co-axial to an axis, which are mutually facing and spaced to provide an interspace. The plates have facing surfaces (6, 7) from which elements (8, 9, 10) for the connection of the same plates transversally extend. Such facing surfaces define, together with the connecting elements, inside the interspace, ventilation ducts in order to cool the disc. The disc (1) comprises a plurality of projections (11, 12) protruding from both facing surfaces of the two plates (3, 4). The projections are circumferentially arranged only in proximity of the outer edges of the plates in correspondence of the outlet of the ventilation ducts. Each projection (11) of a plate (3) is opposed to and aligned with a projection (12) of the other plate (4) along a direction parallel to the axis.