A process is provided for metallizing the hole-wall surface of a through-hole provided in a printed circuit board precursor. In an initial step, the hole-wall surface is pre-treated with an oxidizing agent which micro-roughens it. An electro-conductive polymer film is then formed on the micro-roughened surface by oxidatively polymerizing in situ an acidic solution of an organic monomer with an oxidizing agent previously adsorbed on the board. The polymer film includes dopant anions which are acquired from the monomer solution. Finally, a metal layer is electroplated on the electro-conductive polymer film.