A rhodium(I) diphosphine complex has been anchored on an activated carbon by means of a covalent bond and then it has been tested as catalyst for the hydroformylation of 1-octene. The heterogenization procedure includes the functionalization of the carbon surface to create acid chloride groups where an esterification reaction with the hydroxyl end of a diphosphine ligand (HONP) can take place. Two strategies have been followed: route I : ligand anchorage followed by complex formation (using the [Rh(mu-Cl)(COD)](2) complex as precursor) and route II : synthesis of the rhodium diphosphine complex [Rh(HONP)(COD)]Cl followed by anchorage on the functionalized carbon support. The solid samples, functionalized activated carbon and anchored complexes, have been characterized by XPS and P-31 NMR. The two synthetic routes render catalysts that are active, selective and stable enough to be used in consecutive catalytic runs. The catalyst prepared by route II shows an outstanding behaviour, being fully active and with almost constant selectivity to the linear aldehyde in four consecutive catalytic runs. (C) 2004 Elsevier B.V. All rights reserved.