Here, a novel and simple route to fabricate highly dense arrays of palladium nanodots and nanowires with sub-30 nm periodicity using nanoporous templates fabricated from supramolecular assemblies of a block copolymer, polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) and a low molecular weight additive, 2-(4'-hydroxybenzeneazo) benzoic acid (HABA) is demonstrated. The palladium nanoparticles, which are directly deposited in the nanoporous templates from an aqueous solution, selectively migrate in the pores mainly due to their preferential attraction to the P4VP block covering the pore wall. The polymer template is then removed by oxygen plasma etching or pyrolysis in air resulting in palladium nanostructures whose large scale morphology mirrors that of the original template. The method adopted in this work is general and versatile so that it could easily be extended for patterning a variety of metallic materials into dot and wire arrays.