Revised tables of x-ray mass attenuation and absorption cross sections have been prepared for the elements with atomic numbers one to 94 at selected wavelengths of interest to spectroscopists, microprobe users, diffraction workers, etc. The tables are derived from an x-ray cross section compilation to be published during the summer of 1971. The new compilation is a revision of a previous work and provides photoelectric, coherent scattering, incoherent scattering, absorption component of incoherent scattering and total attenuation cross sections for 94 elements for the photon energy range 0.1 keV to 1 MeV (0.0124 Å to 124 Å). The cross sections for energies greater than 1 keV (12.4 Å) were determined from experimental attenuation data and theoretical scattering cross sections calculated using form factors and incoherent scattering functions based on a relativistic self consistent field method. For hydrogen, the photoelectric absorption cross sections were calculated exactly. Least squares procedures were used to interpolate and extrapolate for elements and photon energies where no experimental data were found. Cross sections for the energy range 0.1 keV to 1 keV (12.4 Å to 124 Å) were calculated using nonrelativistic, single electron, self-consistent field theory with Herman-Skillman bound state wavefunctions, A brief description is given of the assumptions and methods used in preparing the revised compilation, and estimated uncertainties in the cross section are reported. Examples illustrating agreement between tabulated values and experimental data are given and a comparison is made with values taken from earlier x-ray cross section compilations.