The propagation of microwaves in ferrimagnets is affected mainly by the gyrotropic terms of the magnetic permeability tensor, due in this frequency range to ferromagnetic and exchange resonances. It is shown that the change in the gyrotropic terms in the domain wall region leads to the existence of a localized mode propagating close to the domain wall. The domain wall constitutes an optical inhomogeneity for the microwave. The reflectivity and transmittivity of a domain wall are calculated.