Microfabricated magnetoresistive elements based on either the anisotropic or the giant magnetoresistance effect were tested for their frequency dependent resistance noise behavior at room temperature in a dc magnetic field, using a dc sense current. Thermal resistance noise was the dominant noise source above about 10 kHz. At low frequencies the resistance noise was found to be dominated by a1/fcontribution that depends on the applied magnetic field. The1/fnoise is relatively low and field independent when the element is in a saturated state and contains a relatively large and field dependent excess contribution when the magnetic field is in the sensitive field range of the element. The1/fnoise level observed in saturation is comparable to the1/fnoise level found in nonmagnetic metals; the excess noise has a magnetic origin. The variation of the excess noise level with the applied dc magnetic field can be explained qualitatively using a simple model based on thermal excitations of the magnetization direction. ©1997 American Institute of Physics.