In order to further develop a magnetoresistive sensor device (100; 100′; 100″) comprising at least one substrate or wafer (10), in particular at least one silicon wafer, and at least one sensing element (30), in particular at least one A[nisotropic]M[agneto]R[esistive] sensing element and/or—at least one G[iant]M[agneto]R[esistive] sensing element, for example at least one multilayer G[iant]M[agneto]R[esistive] sensing element, said sensing element (30) being arranged on and/or under the substrate or wafer (10), as well as a corresponding method of fabricating such magnetoresistive sensor device (100; 100′; 100″) in such way that an external or extra bias magnetic field to preset the sensing element (10) and/or the magnetoresistive sensor device (100; 100′; 100″) can be dispensed with, it is proposed to arrange at least one magnetic layer (20t, 20b) on (20t) and/or under (20b) the substrate or wafer (10) and at least partially on (20t) and/or under (20b) the sensing element (30), said magnetic layer (20t, 20b) providing at least one bias magnetic field.