The evaluation of ferrites and ferrimagnetic garnets for use in microwave switches and digital phasers requires, in addition to microwave examination, determination of saturation and remanent magnetization, coercive field, and a measure of squareness, including the dependence of these properies on amplitude of actuating fields, temperature, and internal and externally applied stresses. We have developed a novel method which combines the required accuracy and convenience, and by which we are able to examine, on a single specimen, both the low‐field details of hysteresis and the approach to saturation at high fields. The field is produced by a nickel—ferrite electromagnet excited at 60 or 400 Hz, generating a field at amplitudes up to 1000 Oe. The specimen may be a rod, toroid, or other shape. Flux sensing is conventional; sensing of internal field is done by a magnetic potentiometer of special design. Integration is performed by a system incorporating amplifiers which were selected for gain, bandwidth, noise, and drift characteristic adequate to yield substantially distortion‐free hysteresis loops under the stringent requirements of high‐field excitation.