This　paper　extends　the　technique　for　order　preference　by　similarity　to　ideal　solution　(TOPSIS)　for　solving　multi-attribute　group　decision　making　(MAGDM)　problems　under　Atanassov　intuitionistic　fuzzy　set　(IFS)　environments.　In　this　methodology,　weights　of　attributes　and　ratings　of　alternatives　on　attributes　are　extracted　from　fuzziness　inherent　in　decision　data　and　making　process　and　described　using　Atanassov　IFSs.　An　Euclidean　distance　measure　is　developed　to　calculate　the　differences　between　alternatives　for　each　decision　maker　and　an　Atanassov　IFS　positive　ideal　solution　(IFSPIS)　as　well　as　an　Atanassov　IFS　negative　idealsolution　(IFSNIS).　Degrees　of　relative　closeness　to　the　Atanassov　IFSPIS　for　all　alternatives　with　respect　to　each　decision　maker　in　the　group　are　calculated.　Then　all　decision　makers　in　the　group　may　be　regarded　as　attributes　and　a　corresponding　classical　MADM　problem　is　generated　and　hereby　solved　by　the　TOPSIS.　The　proposed　methodology　is　validated　and　compared　with　other　similar　methods.　A　numerical　example　is　examined　to　demonstrate　the　implementation　process　of　the　methodology　proposed　in　this　paper.　©　2011,　IGI　Global.