Site-selective deposition of nanoparticles onto surfaces is desirable for the fabrication of nanoscale devices. For nanoparticles with vastly different numbers of DNA chains on their surfaces, multivalent binding of short-sequence motifs and nonspecific adsorption complicate sequence-specific immobilization from mixtures. A new nanoparticle coating method that suppresses salt-induced aggregation and undesirable binding events is reported. Size-selective sorting of gold nanoparticles up to 60 nm diameter onto nanopatterned surfaces is shown (see figure).