Test　results　on　concrete-filled　square　steel　tubular　stub　columns　with　longitudinal　inner　and　outer　welded　stiffeners　under　concentric　compression　are　presented　in　this　paper.　A　longitudinal　stiffener　was　provided　at　each　side　of　the　tube.　The　main　experimental　parameters　considered　were　the　width-to-thickness　ratio　and　stiffener　rigidity.　Moreover,　empty　tubes　with　or　without　stiffeners,　as　well　as　unstiffened　concrete-filled　square　steel,　tubes　were　also　tested　for　comparison.　Results　from　the　study　indicated　that,　compressive　load　of　the　composite　stub　columns　was　increased　when　stiffeners　were　provided.　The　stiffeners　can　effectively　delay　the　local　buckling　of　the　tube,　as　well　as　improve　the　lateral　confinement　on　concrete　core.