The existence of a ferromagnetic surface layer in antiferromagnetic chromium has been confirmed experimentally by detecting surface magnetoplasma waves (SMPW) via the method of attenuated total reflection. The optical configuration consisted of a half cylinder heavy dense flint prism −900 A˚ MgF2dielectric thin film–optically opaque chromium film. The dispersion curve for surface plasma waves (SPW) was obtained by measuring the reflectivity as a function of angle of incidence at constant photon energy in the range of 2.0–4.0 eV. Measurement of the normalized reflectivity difference &dgr; due to a low frequency oscillating magnetic field applied perpendicular to the direction of propagation of the SPW indicates the presence of SMPW and therefore a ferromagnetic surface layer. Experimentally &dgr; maximizes atE=3.25 eV and varies linearly with the applied magnetic field to 500 Oe. In the absence of SPMW &dgr; is less than 1&percent; of the &dgr; measured in the presence of SMPW in the same photon energy range.