A process for the production of a substrate having antimicrobial properties is described. It comprises a step consisting of the deposition of a metal non-gelling layer comprising an inorganic antimicrobial agent, starting from a precursor, in metal, colloid, chelate or ion form on at least one of the surfaces of the metallic substrate; and a step consisting of the diffusion of the agent into said at least one surface of the substrate by thermal treatment. Alternatively, the substrate may be coated with an underlayer or a topcoat and the diffusion occurs either in the underlayer or in the topcoat. Metallic substrates having antimicrobial properties are also described. In particular, a substrate exhibiting a bactericidal activity measured in accordance with standard JIS Z 2801 of higher than log 2.