The　surface　of　carbon　black　was　modified　by　oxygen　plasma　treatment　for　different　times　(10,　20　and　30　min).　In　order　to　increase　the　applicability　of　carbon　black　(CB),　functional　groups　were　grafted　on　the　generally　inert　surface　of　CB　using　oxygen　plasma.　The　surface　compositional　and　structural　changes　that　occurred　on　CB　were　investigated　by　SEM,　FT-IR,　Raman　spectroscopy,　XRD　and　BET.　Subsequently,　CB　reinforced　polycarbonate　(PC)/acrylonitrile-butadiene-styrene　(ABS)　composites　were　prepared　by　internal　batch　mixing　with　the　addition　of　different　content　of　CB　(3,　6,　9,　12　wt%).　The　morphology　of　PC/ABS/CB　(7/3/6　wt%)　nanocomposites　was　studied　through　scanning　electron　microscopy.　Observations　of　SEM　images　showed　that　the　plasma-treated　CB　had　a　better　dispersion　in　the　blend　matrix.　Moreover,　the　mechanical　tests　showed　that　the　tensile　strength　and　impact　strength　were　improved　by　32.4%　and　22.5%,　respectively,　with　the　addition　of　plasma-treated　CB.　In　addition,　the　thermal　stability　was　improved　and　glass　transition　temperatures　of　both　PC　and　ABS　increased　as　shown　by　TGA　and　DSC,　respectively.　©　2015　Published　by　Elsevier　B.V.