Growth and adhesion mechanisms of Ni clusters electrodeposited on three different carbon-based substrates have been studied. Glassy carbon, carbon paper and PAN-based fibres have been used as working electrodes and Ni clusters have been electrodeposited from a NiCl(2 center dot)6H(2)O. Ni reduction on carbon substrates has been studied by cyclic voltammetry, chronocoulometry and in situ SERS, whereas the morphological and structural characterization of the interface between Ni clusters and carbon-based substrates has been performed by High Resolution TEM. From our results we can conclude that the precipitation of Ni hydroxides and basic salts in the unbuffered catholyte promotes the adhesion of Ni clusters on the carbon-based substrates considered in this study. This feature of the investigated Ni clusters electrodeposition suggests that it may be a suitable fabrication route for applications in catalytic processes, such as metal-particle catalysed growth of carbon nanotubes. (C) 2008 Elsevier B.V. All rights reserved.