Dendritic DNA molecules, referred to as DNA dendrons, consist of multiple covalently linked strands and are expected to improve the cellular uptake and potency of therapeutic oligonucleotides because of their multivalency. In this study, we developed an efficient synthetic method for producing DNA dendrons using strain-promoted azide-alkyne cycloaddition. Integration of the antitumor aptamer AS1411 into DNA dendrons enhanced cellular uptake and antiproliferative activity in cancer cells. These findings demonstrate that the incorporation of multivalent aptamers into DNA dendrons can effectively boost their therapeutic effects.