<p>We consider the problem of oblique incidence of a Gaussian beam on a plane-parallel dielectric structure using a multi-beam method that accounts for the contribution of waves rereflected within the layer, which significantly influence the resulting amplitude and phase distributions of the reflected wave. This approach is particularly useful for analyzing electromagnetic wave transmission through multilayer dielectric structures. A numerical method for calculating the reflected beam, based on the decomposition of the beam into plane waves using the fast Fourier transform and including the losses in each dielectric layer, is presented here. The problem is solved within the framework of the parabolic approximation. Components of the Gaussian beam spectrum with small transverse wavenumbers (compared with the wavenumber in free space) are taken into account. The arbitrary polarization of a plane wave reflected from a dielectric layer is also included.</p>