We have demonstrated nonreciprocity in a magneto-optic waveguide by measuring the polarisation of the light emerging out of the channel waveguide, where a magnetic field was applied along the propagation direction. Nonreciprocity in an optical waveguide, in which the phase matching between the orthogonally polarised modes is not satisfied, leads to the opposite rotation of the major axis of the ellipse of the output light polarisation as reversing the propagation direction.