Abstract: A profile-section support system, in particular, for industrial-fair and exhibition construction, has hollow profile-section supports (10) of polygonal cross section, which on at least one of their outer sides (14, 15, 16, 17), along the edges with ribs (18, 19, 20, 21), which between them enclosed grooves (22) with peripheral undercuts for anchoring fast-action connecting elements (43, 44, 63) for connecting further profile-section supports (10) or other parts, and which in the corner regions in the interior are provided with inner corner grooves (23). Spreading apart of the ribs (18, 19, 20, 21) with deformation of the hollow profile-section side (14, 15, 16, 17) enclosed between them is thereby possible. On outer sides (14, 16, 17) adjoining one another of the hollow profile-section supports (10), ribs are disposed. Two ribs (18, 19, 20, 21) on the edge, between the adjacent outer sides (14, 16, 17) of the hollow profile-section support (10), between them enclose an outer corner groove (24).