A thin film alloy of Ni‐Fe‐Co is etched such that it resembles electrically a Wheatstone bridge except that the arms of the bridge are magnetoresistive. The resistance of one arm increases and the other decreases when in the presence of a magnetic field. The primary feature of this magnetometer is its fast response time. Tests have shown that it has a flat response to alternating magnetic fields with frequencies as high as 65 MHz which was the limit of our test equipment. We have reason to believe that our present system will measure pulses with risetimes as fast as 4 nsec with less than 5% error.