The present invention provides a new class of non-viral transduction vectors that can be used for both in vivo and in vitro applications. The present invention also provides a gene transfer vector that has comparable efficiency to a viral vector without the potential for a life-threatening immune response. Complexes according to the invention or portions thereof, can comprise a cellular delivery molecule or agent that can facilitate the translocation of the complex or portion thereof into cells. In some embodiments, cellular delivery molecules for use in the present invention may comprise one or more polymers of the present invention, e.g., polyamides, dendritic macromolecules and carbohydrate-containing degradable polyesters.