Specific features of deformation of amorphous and nanocrystalline metallic alloys influenced by pulsed electric current were studied. It has been discovered that passing pulse electrical current causes a momentary relief of mechanical stresses in loaded samples with its subsequent reduction. The effect of aggressive media (20 % solutions of H2SO4 and HNO3) on the value of mechanical stress drop in samples of amorphous cobalt-based alloys and nanocrystalline iron-based alloy was also investigated. It depends on the tensile stess – tensile strain and occurs when electric current pulses are passing. The paper determines dependence of the mechanical stress value in tested materials on the density of pulsed electric current. It also investigates the structural and morphological state of the alloy surface after its exposure to aggressive media of different concentration.