Differential (p,xn) cross sections are measured for 800-MeV protons incident on thin targets of depleted uranium and of natural beryllium, boron, carbon, nitrogen, oxygen, aluminum, iron, cadmium, tungsten, and lead. Measurements for neutron energies from 0.3 to 800 MeV are made at angles of30, 60, 120, and 150 deg. Time-of-flight techniques are used to determine the neutron energy spectra, and particular effort is made to identify and discriminate against background contributions. Comparisons of the experimental data with calculations using the high-energy transport code (HETC) intranuclear-cascade evaporation model show good agreement for the heaviest elements (tungsten, lead, and uranium), but significant discrepancies exist for the light elements, especially in the evaporation region.