The x-ray standing-wave technique through detection of surface-sensitive Auger electrons has determined the surface reconstruction of clean InP(110). Using the back-reflection diffraction geometry from (220) planes, we find the perpendicular displacements of the surface P and In atoms to be +0.18\ifmmode\pm\else\textpm\fi{}0.1 and -0.48\ifmmode\pm\else\textpm\fi{}0.08 \AA{}, respectively, from their unrelaxed bulk positions. The use of low-energy x rays combined with a novel method of data analysis opens the general problem of surface reconstruction to study by this technique.