Experimental and analytical research on erosion of 1100-0 aluminum, 316 stainless steel, commercially pure annealed nickel, and 6A1-4V titanium (annealed) is summarized. The erosion is caused by the multiple impacts of a water jet in a rotating disk facility. The relationship between the velocity of impact and the number of impacts at which visible indentations were observed is compared with the high-frequency fatigue strength of these materials. The experimentally observed rates of erosion are compared with a recently developed theory of erosion. The fatigue life distribution curves also are included. The peak rate of erosion varies approximately as the fifth power of the velocity, whereas the time at which the peak rate is observed varies as the one-fifth power. The cavitation erosion strength and liquid impact erosion strengths of these materials also are compared.