Simple domain structures were observed in iron‐silicon and cobalt‐iron single crystals by three techniques using polarized neutrons. The first method involves scanning the specimen with a fine beam and measuring the depolarization suffered by the beam after transmission: it can only detect regions where the magnetization direction deviates from the direction of polarization of the beam, and cannot differentiate domains with antiparallel magnetization. The second method, based on the determination of the ratio of the Bragg‐diffracted intensities when the polarization of a fine beam is reversed, provides, when the specimen is scanned, a map of the domains. The third technique, polarized neutron diffraction topography, provides photographs of the domain structure. The possibilities of these techniques for the observation of domains within bulk specimens are discussed.