The approach to the ultimate strength of metals is determined experimentally. The ultimate strength of metals was calculated using a realistic wide-range equation of state. The strength of metals was measured using shock waves created in aluminum and copper foils with a short-(20-100 ps) pulse high-power laser. The strength of the materials was determined from the free-surface-velocity time history, which was measured with an optically recording velocity interferometer system. The strain rates in these experiments were in the range (1.5-5) X 108 s-1.