A CNT-AuNP hybrid has been synthesized through the Michael addition reaction between thiol-functionalized single-wall CNT and small water-soluble Maleimide-AuNP. The resilience and stability of this hybrid nanosystem is ensured by a covalent bond linking the nanoparticle to the CNT and by the fact that the functionalization reaction involves the organic shell of the AuNP and not its metallic core.