The　objective　of　this　paper　is　to　investigate　the　performance　of　slender　square　reinforced　concrete　(RC)　columns　strengthened　with　carbon　fibre　reinforced　polymer　(CFRP)　jackets　subjected　to　eccentric　loading.　Tests　were　conducted　on　eight　RC　columns　strengthened　with　CFRP　jackets,　and　another　eight　unstrengthened　ones　served　as　reference　specimens.　The　main　variables　explored　in　this　test　programme　include:　(a)　load　eccentricity　(0-150　mm);　(b)　with　or　without　CFRP　strengthening;　and　(c)　CFRP　configuration　(unidirectional　and　bidirectional).　Compared　to　those　unstrengthened　RC　specimens,　the　test　results　showed　that　no　obvious　strength　increase　was　observed　for　specimens　confined　by　unidirectional　CFRP　jackets,　while　an　increase　of　22.8-61.8%　was　obtained　for　those　strengthened　by　bidirectional　CFRP　jackets.　The　longitudinal　fibres　were　effective　in　enhancing　load-carrying　capacity　of　slender　RC　columns　subjected　to　eccentric　loading.