The experimental and computer-simulation study of the magneto-optical properties (equatorial Kerr effect) of Fe/Zr and Co/Zr multilayered films was carried out. Drastic changes in the magneto-optical properties of the Fe/Zr and Co/Zr multilayered films were observed with the ferromagnetic sublayers that had less than the critical thickness. Such a behavior is connected with a polycrystalline-amorphous transformation in these sublayers. An annealing of the multilayered him led to a significant increase in the equatorial Kerr effect value which is caused by a partial crystallization of the amorphous Fe or Co sublayers. The real interface structures of the Fe/Zr and Co/Zr multilayered films were estimated by a fitting procedure between the experimental and the computer-simulated equatorial Kerr effect spectra of the multilayered films.