It has been observed that the magnetic anisotropy direction of certain thin Permalloy films prepared bythe thermal decomposition of nickel and iron carbonyls can be rotated through 90 deg at room temperatureby fields less than 10 oe. The experimental conditions under which these films were prepared suggest thatthis phenomenon is due to the presence of carbon. The relaxation time for the rotation of the anisotropyaxis was calculated from the time dependence of the induction and found to be 10 msec. A simple modelhas been developed which relates the anisotropy rotation to specific domain wall configurations and to theestablishment of a “directional order” among interstitial carbon atoms.