To determine how the ac and dc magnetic properties are affected by elastic strain, the magnetic properties in the rolling direction of Epstein strips of elastically bent grain‐oriented 3% silicon iron were measured in an Epstein frame and in a Carr single‐strip permeameter. As the degree of bending becomes more pronounced, the coercive force and the ac core loss increase and the permeability decreases. The domain theory gives a rather simple approximate interpretation of the permeability data for magnetic intensities between one and ten oersteds.