In the articles surface polaritons are investigated in semimagnetic semiconductors in a phase of antiferromagnetic ordering. The influence of the external static magnetic field and the electron concentration on the dispersion properties of the surface polaritons is determined. It is shown that the surface polaritons can have a negative dispersion, independent of the direction of propagation in the Voigt geometry. A new method based on excitation of the surface polaritons in the seminiagnetic semiconductors is proposed for determination of the antiferromagnetic resonance frequency.