the aim of the present work is intended to evaluate the effect of static magnetic field (SMF) on rat's kidney. The rats were exposed to SMF of intensities of 10, 14, 18 and 22 milliTisla (mT) for a whole week for one hour daily. The dielectric properties, permittivity (έ), electrical bioconductivity (σ), loss tangent (tanδ), and relaxation time (τ), were measured to the rat’s kidneys over frequency range of 1 kHz to 1 MHz, before, immediately after exposure, and after one week of exposure. The results showed that there are significant differences in the dielectric properties of samples under investigation compared to the control (no SMF irradiation). The relaxation time showed significant variants of rat's kidney upon irradiation to SMF intensities, especially the 10 mT dose.