We propose an explanation of the anomalous growth of plasticity in ferromagnets near the Curie point. We demonstrate that this effect is caused by spin-dependent detachment of dislocations from obstacles under the influence of the internal magnetic induction. Magnetization fluctuations grow in the vicinity of the Curie point, yielding an increase in the detachment probability and, hence, an increase in the plasticity. We apply this model to a description of the temperature behaviour of the critical stress in nickel and of (...) the microhardness of gadolinium. An external magnetic field suppresses the magnetization fluctuations and, hence, may suppress the above singularities. (shrink)