We study the influence of the interfaces on the dispersion relation, energy and power flow of polaritons propagating in coaxial cylinders. We consider an infinite coaxial cylinder of internal and external radii designated by a and b, respectively, submitted to a magnetic dc field applied parallel to the z-axes. The presence of a magnetic field causes significant alterations in the modes of propagation of polaritons. The numerical results are obtained for the surface polaritons propagating in semiconductors cylinders of GaAs in presence of magnetic fields of 5 kG.