Hybrid prefabricated foundation for towers, comprising a circular slab made in-situ, and arranged therein a set formed by a cylindrical pedestal and by a plurality of ribs joined by an joining end to said pedestal, and arranged radially on the slab, the pedestal being configured for the fixing of a tower, wherein the set of pedestal and ribs is constituted by - a plurality of upper pieces prefabricated, which in turn comprise a rib, and attached to the upper part of its connection end an upper pedestal sector (4 ') in such a way that a portion of the upper pedestal sector (4 ') remains on each side of the rib, and a plurality of prefabricated lower pieces, which in turn comprise a rib, and attached to the lower part of its connection end a lower pedestal sector (4") in such a way that a portion of the lower pedestal sector (4") remains on each side of the rib, characterized in that the upper pieces and the lower pieces being arranged radially alternated with each other, alternately vertically overlapping each other, each portion of the upper pedestal sector (4 ') of each upper piece being arranged on a portion of the lower pedestal sector (4 ") of each of the lower pieces adjacent to each upper piece, in such a way that the upper pedestal sectors (4 ') of the upper pieces are arranged on the lower pedestal sectors (4 ") of the adjacent lower pieces, the upper pedestal sectors (4 ') and the lower pedestal sectors (4' ') forming the pedestal, - the pedestal comprising: - a plurality of anchor holes parallel to the axis of the pedestal and passing through the entire height of said pedestal, configured to house anchor bolts of the tower, for anchoring said tower to the pedestal, and - a plurality of post-tensioning bolts housed in a plurality of housings arranged on the pedestal, parallel to the axis of said pedestal and passing through thereof. wherein the set of pedestal and ribs is constituted by - a plurality of upper pieces prefabricated, which in turn comprise a rib, and attached to the upper part of its connection end an upper pedestal sector (4 ') in such a way that a portion of the upper pedestal sector (4 ') remains on each side of the rib, and a plurality of prefabricated lower pieces, which in turn comprise a rib, and attached to the lower part of its connection end a lower pedestal sector (4") in such a way that a portion of the lower pedestal sector (4") remains on each side of the rib, characterized in that - a plurality of upper pieces prefabricated, which in turn comprise a rib, and attached to the upper part of its connection end an upper pedestal sector (4 ') in such a way that a portion of the upper pedestal sector (4 ') remains on each side of the rib, and a plurality of prefabricated lower pieces, which in turn comprise a rib, and attached to the lower part of its connection end a lower pedestal sector (4") in such a way that a portion of the lower pedestal sector (4") remains on each side of the rib, characterized in that the upper pieces and the lower pieces being arranged radially alternated with each other, alternately vertically overlapping each other, each portion of the upper pedestal sector (4 ') of each upper piece being arranged on a portion of the lower pedestal sector (4 ") of each of the lower pieces adjacent to each upper piece, in such a way that the upper pedestal sectors (4 ') of the upper pieces are arranged on the lower pedestal sectors (4 ") of the adjacent lower pieces, the upper pedestal sectors (4 ') and the lower pedestal sectors (4' ') forming the pedestal, - the pedestal comprising: - a plurality of anchor holes parallel to the axis of the pedestal and passing through the entire height of said pedestal, configured to house anchor bolts of the tower, for anchoring said tower to the pedestal, and - a plurality of post-tensioning bolts housed in a plurality of housings arranged on the pedestal, parallel to the axis of said pedestal and passing through thereof. - the pedestal comprising: - a plurality of anchor holes parallel to the axis of the pedestal and passing through the entire height of said pedestal, configured to house anchor bolts of the tower, for anchoring said tower to the pedestal, and - a plurality of post-tensioning bolts housed in a plurality of housings arranged on the pedestal, parallel to the axis of said pedestal and passing through thereof.