A method for making a supporting base for medical instruments, comprising the following operating steps: preparing a supporting layer comprising its own visible front surface and its own rear surface opposite to the visible surface; making a plurality of holes through the supporting layer from the front surface to the rear surface; characterized in that it comprises the steps of: cutting on the rear surface at least one track extending along a predetermined path passing through at least one group of holes in order to place them in communication with each other through the track; injecting gripping material at least at one injection point positioned along the track on the rear surface in such a way to position a gripping portion, at least in part, inside the track and at the group of holes in such a way as to fill the track with the gripping portion realizing a gripping portion on the rear surface; the gripping material being in the semi-solid or liquid state for introduction and expansion along the track in the rear surface and inside at least part of the holes of the group in such a way as to fill them; waiting the solidification of the gripping material on the rear surface in such a way to realize an irreversible joining of the gripping portion to the rear surface to form a single body with the supporting layer to prevent the dirt inserting between the supporting layer and the gripping portion; making at least one opening at each hole and passing through the gripping portion for inserting, in use, at least one medical instrument in such a way that the gripping portion defines a gripping area for the medical instrument. preparing a supporting layer comprising its own visible front surface and its own rear surface opposite to the visible surface; making a plurality of holes through the supporting layer from the front surface to the rear surface; characterized in that it comprises the steps of: cutting on the rear surface at least one track extending along a predetermined path passing through at least one group of holes in order to place them in communication with each other through the track; injecting gripping material at least at one injection point positioned along the track on the rear surface in such a way to position a gripping portion, at least in part, inside the track and at the group of holes in such a way as to fill the track with the gripping portion realizing a gripping portion on the rear surface; the gripping material being in the semi-solid or liquid state for introduction and expansion along the track in the rear surface and inside at least part of the holes of the group in such a way as to fill them; waiting the solidification of the gripping material on the rear surface in such a way to realize an irreversible joining of the gripping portion to the rear surface to form a single body with the supporting layer to prevent the dirt inserting between the supporting layer and the gripping portion; making at least one opening at each hole and passing through the gripping portion for inserting, in use, at least one medical instrument in such a way that the gripping portion defines a gripping area for the medical instrument. cutting on the rear surface at least one track extending along a predetermined path passing through at least one group of holes in order to place them in communication with each other through the track; injecting gripping material at least at one injection point positioned along the track on the rear surface in such a way to position a gripping portion, at least in part, inside the track and at the group of holes in such a way as to fill the track with the gripping portion realizing a gripping portion on the rear surface; the gripping material being in the semi-solid or liquid state for introduction and expansion along the track in the rear surface and inside at least part of the holes of the group in such a way as to fill them; waiting the solidification of the gripping material on the rear surface in such a way to realize an irreversible joining of the gripping portion to the rear surface to form a single body with the supporting layer to prevent the dirt inserting between the supporting layer and the gripping portion; making at least one opening at each hole and passing through the gripping portion for inserting, in use, at least one medical instrument in such a way that the gripping portion defines a gripping area for the medical instrument.