The magneto-optical Kerr effects in magnetic multilayered structures containing double-negative metamaterials are investigated by using 4×4 transfer-matrix method. The azimuth rotations and the figure of merit of the magneto-optical effects are calculated as a function of the thickness, permeability, and permittivity of the layers. It is shown that the magneto-optical effects are not only enhanced largely for the present system in comparison with those in the magnetic multilayered structures containing general metal materials but a giant Kerr rotation near 90° is also observed when the thickness of the sample is far less than the resonant wavelength. The physical origination for such a phenomenon is also analyzed. This means that we can obtain large magneto-optical Kerr effects at very thin magnetic film by using the double-negative metamaterials, which benefit the application in magnetic-optical recording.