Abstract: A process for electro depositing bioactive coatings, such as calcium phosphate or aluminum oxide, onto conductive substrates, such as prosthetic implant devices, is described. An electrolyte bath containing an aqueous solution of the desired oxide or phosphate is prepared with an inert anode such as a platinum anode. A porous or non porous substrate, such as a stainless steel or titanium implant is used as the cathode and a D.C. potential is applied so as to raise the interfacial pH at the cathode sufficient to precipitate the desired oxide or phosphate thereon as a dense adherent film.