New molecular simulation data tire reported for the compressibility factors of hard spheres covering the isotropic liquid, metastable fluid and solid ranges of density. These data provide a comprehensive set of values for the development of hard-sphere equations of state. In particular, they represent a substantial increase in the data available at high isotropic liquid densities. A comparison is reported with examples of accurate hard sphere equations. In contrast to literature comparisons, which are weighted towards existing lower density data, including these new higher density data indicates that the overall accuracy of current equations of state is considerably less than previously reported. (C) 2004 American Institute of Chemical Engineers.