Metal nanoparticles on carbon nanotubes (CNTs) are expected to be efficient catalysts for several industrially important processes. Here, the successful preparation of well-dispersed Ru-CNT nanocomposites-which are subsequently demonstrated to be very active for the hydrogenation of benzene to cyclohexane-using (RuCl3H2O)-H-. as the precursor is reported. The Figure shows a transmission electron microscopy image of nanocomposites used four times as a catalyst.