The　use　of　hollow　structural　steel　(HSS)　columns　filled　with　concrete　has　become　widespread　in　the　past　few　decades.　However,　these　members　are　susceptible　to　the　effects　of　pre-load　on　the　steel　tubes　during　construction.　Nineteen　concrete-filled　HSS　columns　with　the　steel　tubes　subjected　to　pre-load　have　been　tested.　An　attempt　to　predict　the　load-deformation　behaviour　of　concrete-filled　HSS　columns　with　the　steel　tubes　subjected　to　pre-load　is　proposed　in　this　paper.　A　comparison　of　the　results　calculated　using　this　model　shows　good　agreement　with　the　test　results.　The　theoretical　model,　and　the　influence　of　the　pre-load　ratio,　slenderness　ratio,　steel　ratio,　as　well　as　the　strength　of　the　materials　are　discussed.　Finally,　formulas　for　the　calculation　of　the　ultimate　strength　of　concrete-filled　steel　tubular　columns　with　the　steel　tubes　subjected　to　pre-load　are　developed;　such　formulas　should　be　suitable　for　incorporation　into　building　codes.　(C)　2003　Elsevier　Ltd.　All　rights　reserved.