Abstract: The process of electroless plating of polymers containing units derived from at least one member of the group consisting of acrylonitrile, butadiene and styrene, is carried out in an environment free of chromium ions, by the sequential steps of roughening and activating the surface of the polymer by contacting the same with an aqueous solution of a concentrated sulfur acid, of concentrated nitric acid or of concentrated phosphoric acid, in the presence of noble metal ion and an oxidant selected from the group consisting of nitric acid, hydrogen peroxide and persulfates. This is followed by an aqueous suspension of Pd.sup.0 and then by the conventional chemical metallization.