A medical guide wire is provided having a wire core made, for example, of MR-invisible material and a sheath that surrounds the wire core at least sectionally and so as to be in touching contact therewith. The sheath can have a multilayer structure which has at least two solid material layers and/or fiber layers which are formed by different, MR-invisible plastics materials. The MR marker has at least one MR marker element which is integrated at least partially into the multilayer structure of the sheath or is surrounded thereby.
