Polychlorinated aliphatic or aromatic compounds are hydrodehalogenated under mild conditions (T= 303-343 K; pH(2) = 0.1 MPa) in methanol containing an organic or inorganic base, using intercalated Pd(II) and Rh(III) as metal catalysts. Both "naked" ions inserted into gamma-Zirconium phosphate (gamma-ZrP-M) and their complexes with 2,2'-bipyridyl (bipy) or 1,10-phenanthroline (phen), gamma-ZrP-M-L (L = bipy, phen) intercalated into the same matrix have been used. A recently prepared material containing intercalated octadecyltrimethyl ammonium ion, gamma-ZrP-C-18 (C-18= C18H37N(CH3)(3)(+)), with an unusually large interlayer distance has been also used as support. The catalytic activity depends on the metal, the ligand and the base. The best results have been obtained upon using NEt3 as the base. Pd-compounds are more active but less stable than the analogous Rh-compounds. Bipy and phen ligands play a dual role: in fact, they reduce the catalytic activity, but they increase the stability over time and the recycling possibility of the catalyst. Conversely, the catalyst based on naked metal ions inserted into gamma-ZrP charged with surfactant ions exhibits an initial catalytic activity comparable with that of the materials described above, but it looses more rapidly its activity. (C) 2004 Elsevier B.V. All rights reserved.