The method relates to the manufacture of a reinforced diamond-coated cable for cutting structures and materials of steel, concrete, steel and concrete, stone materials or the like, in which such diamond-coated cable comprises a plurality of outer strands (101) of metal material such as steel or the like wound in a helix around an inner central strand (201) and a series of sheaths (2) inserted along such outer strands (101) and having on their external profiles (202) projecting members of strongly abrasive materials such as industrial diamonds or the like. The method comprises the following stages: a) at least partly unwinding the outer strands (101) between each pair of successive sheaths (2′, 2″) so as to space them apart to create a free space (3, 3′) between the outer strands (101) and the central strand (201), b) inserting a rigid mechanical interference member (4, 6) in the space between one outer strand and the other and in the said free space (3, 3′) to create an enlarged zone of suitable diameter (D) between each pair (2′, 2″) of successive sheaths, c) again helically winding the outer strands (101) around such rigid mechanical interference member (4, 6).