A system for connection between parts of a structure, comprising providing the parts (1, 2, 3 and 4) to be connected with elements in the form of ribs or drill holes (5), on the surfaces of zones or areas of connection of said parts; placing the parts to be connected in a mold (7), in the relative position they will occupy within the structure, with the ribs or drill holes (5) inside said mold; and injecting, into the mold, a resin or melted adhesive plastic such that it fills the drill holes (5), the inner holes of the parts and the spaces (8) defined therebetween.