A novel approach has been developed to synthesize gold-coated iron oxide nanoparticles. Fe3O4 nanoparticles were initially prepared by co-precipitation method and subsequently coated with gold layer under oleylamine reduction of AuCl4- at room temperature. The core-shell nanoparticles showed magnetic recoverable catalytic activity for the reduction of 4-nitrophenol with NaBH4. (C) 2009 Elsevier Ltd. All rights reserved.