Carbon nanotubes are an emerging class of nanomaterials that are receiving enormous attention in the field of biomedicines due to their biocompatibility, degradability, cell penetrating abilities, and, more specifically, their remarkable ability to localize in the nucleus of the cell without the need of nuclear localizing signals. They are used as drug and gene delivery agent for in vitro studies; however, their transfection efficiencies in vitro are still questionable. We report here the surface functionalization of single-walled carbon nanotubes (SWNTs) with cationic glycopolymers and their use as an in vitro gene transfer agent. The copolymer modified SWNTs are found to be biocompatible and exhibit transfection efficiencies that are comparable to the commercially available agent lipofectamine 2000.