Test　results　on　concrete-filled　steel　tubular　stub　columns　with　inner　or　outer　welded　longitudinal　stiffeners　under　axial　compression　are　presented　in　this　paper.　The　research　was　mainly　focused　on　square　hollow　section　(SHS)　columns;　two　rectangular　hollow　section　(RHS)　columns　were　also　tested.　A　longitudinal　stiffener　was　provided　on　each　side　of　the　stiffened　SHS　column,　while　only　two　stiffeners　were　welded　to　the　longer　sides　of　the　stiffened　RHS　column.　The　main　experimental　parameters　considered　were　the　height-to-thickness　ratio　and　stiffener　rigidity.　In　addition,　empty　tubes　with　or　without　stiffeners,　as　well　as　unstiffened　concrete-filled　steel　tubes　were　also　tested　for　comparison.　Requirements　for　stiffener　rigidity　are　developed　by　modifying　a　formula　presented　in　the　literature.　Existing　theoretical　model　and　design　codes　were　used　to　predict　the　load　versus　axial　strain　relationships　and　load-carrying　capacities　of　the　adequately　stiffened　composite　sections　respectively;　reasonable　results　were　achieved.　(c)　2005　Elsevier　Ltd.　All　rights　reserved.