To　investigate　the　inhibitory　effects　of　dumb-bell　decoy　oligodeoxynucleotides(ODNs)　targeting　NF-kappaB　on　the　transcriptional　activity　of　NF-kappaB　binding　to　its　cis-elements,　growth　of　multiple　myeloma　cells　8266　and　the　expression　of　IL-6　in　8266　cells.The　inhibitory　effects　of　dumbbell　decoy　ODNs　targeting　NF-kappaB　on　the　transcriptional　activity　of　NF-kappaB　was　detected　by　electrophoretic　mobility　shift　assay(EMSA).　8266　cells　were　randomly　divided　into　8266　cells　of　passage　(control),　dumb-bell　decoy　ODNs　treatment,　and　cationic　liposome　treatment　groups.　Dumb-bell　decoy　ODNs　of　2,　4　and　8　mg/L　were　cultured　respectively　into　8266　cells　via　cationic　liposome　vector.　Then,　the　transfected　8266　cells　and　their　supernatant　were　collected　at　8,　12　and　18　h.　IL-6　expression　was　measured　by　ELISA.　Effect　of　decoy　ODNs　on　the　growth　of　8266　cells　stimulated　with　IL-6　was　measured　by　MTT　Colorimetry　assay.Dumbbell　decoy　ODNs　effectively　inhibited　the　binding　of　NF-kappaB　to　its　cis-elements　in　vitro.　Different　doses　of　decoy　ODNs　(2,　4　and　8　mg/L)　had　different　inhibitory　effects　on　IL-6　expression　in　8266　cells.　After　decoy　ODNs　had　been　transfected　into　8266　cells　stimulated　by　IL-6　via　cationic　liposome　vector,　both　the　growth　of　8266　cells　and　activity　of　IL-6　were　inhibited.Dumb-bell　decoy　ODNs　can　effectively　inhibit　the　growth　of　8266　cells　and　decrease　the　expression　of　IL-6　in　myeloma　cells　through　the　inhibiting　NF-kappaB　activity.