This work reports the synthesis of surface-modified iron oxide magnetic nanotubes (Fe3O4NT) with poly(amido amine) dendrimers of the third generation (PAMAM-G3) as novel nanomaterials for potential drug-delivery applications. Fe3O4NT were obtained by reduction of alpha-Fe2O3 nanotubes, which were synthesized following a hydrothermal strategy using SO42-/H2PO4- to control the size and morphology of the prepared materials. Fe3O4NT were further functionalized with PAMAM-G3 moieties using a silane coupling agent. Pristine and PAMAM-modified Fe3O4NT were characterized through TEM, FTIR, XRD, N-2 adsorption-desorption isotherms and VSM measurements, which confirmed the nanotubular morphology and magnetic behavior for both systems, and TGA analyses, which revealed a PAMAM grafting percentage of 16.8%. The effect of PAMAM conjugation on the adsorption and release properties of Fe3O4NT was examined using silibinin as model poorly soluble drug compound. Our results revealed that PAMAM grafting increased the maximum amount of adsorbed drug from 675 mg g(-1) in pristine Fe3O4NT to 825 mg g(-1) in PAMAM-Fe3O4NT. These quantities exceed by far the drug-loading capacity of other pristine and PAMAM-modified nanotubular systems, which constitutes a relevant outcome for the present study.