Intensity and exchange-induced scattering asymmetry versus energy profiles have been calculated for spin-polarized low-energy electron diffraction (SPLEED) from ferromagnetic Fe(110) p(2 × 2)- S. The strong sensitivity of our asymmetry results to the magnetization of the topmost substrate layer suggests SPLEED as a powerful probe of the effect of chemisorption and adsorbate-induced substrate reconstruction on surface ferromagnetism.