In this paper we analyze the distinctive features of the plane waves propagation in an infinite omega medium and the behavior of a planar interface under plane wave excitation conditions. With regard to the propagation of plane wave in an infinite omega medium we provide the dispersion equation, the formal eigenvectors expressions as functions of the eigenvalues (propagation constant, wavenumbers), the conditions on the constitutive relations parameters and the related directions for which the regime of bimodal propagation degenerates into a monomodal one. The considered interface problem is typical of the electromagnetic situation in which a semi-infinite space filled with an isotropic medium, described by the electromagnetic parameters ε, μ, borders on another semi-infinite space filled with a particular bianisotropic medium, referred as pseudochiral or omega. By applying the phase matching conditions at the interface (boundary conditions) we derive the (general) relations between the transmission angle and the incident one of the electromagnetic field in the omega medium. Moreover, we derive as well the total reflection conditions, both for the first and the second eigenwave, the expressions for the incidence and the related transmissions angles, in omega medium, for the regime of monomodal propagation (for which the regime of monomodal propagation holds). Finally, the formal expression of the dyadic reflection and transmission coefficients is given.