The natural ferromagnetic resonance reveals large residual stresses appearing in the microwire core in the course of casting. These stresses, together with the magnetostriction, determine the magnetoelastic anisotropy. Beside the residual internal stresses, the natural ferromagnetic resonance frequency is influenced by external stresses applied to the microwire or to the composite containing the latter (the so-called stress effect).The dependence of the natural ferromagnetic resonance frequency on the deformation of the microwires is proposed to be used in the distant diagnostics of dangerous deformations of critical infrastructure objects