The corrosion resistance of 31 fe-, ni-, al-, cu-, ti-, and mo-base alloys was characterized and evaluated as part of research to determine suitable construction materials for geothermal resource recovery plants. General, crevice, pitting, weld, and stress corrosion studies were carried out at 105 deg and 232 deg c in deaerated brines and in brines containing o2, co2, and ch4. These low- and high-salinity brines are representative of those found in the Imperial Valley, California. General corrosion rates in deaerated brines at 105 deg and 232 deg c were usually below 5 mpy except for carbon steel, the low-alloy steels, monel 400, 70-30 cupronickel, and the aluminum-base alloys. Dissolving co2 and ch4 in the brines at 232 deg c had little effect, but dissolving o2 seriously increased stress corrosion cracking, crevice corrosion, and, except for the ti-base alloys, pitting. In deaerated brines at 232 deg c welds in several fe-, ni-, and ti-base alloys corroded at rates comparable to the general corrosion rates of the alloys, but the addition of o2 to the brine increased weld corrosion rates in inconel 625 and e-brite 26-1. In the deaerated Salton Sea KGRA-type brine at 232 deg c, e-brite 26-1, inconel 625, hastelloy s, hastelloy g, hastelloy c-276, ticode-12, ti-0.2Pd, ti-2ni, ti-1.7W, and tzm were most corrosion resistant; in oxygenated Salton Sea KGRA- type brine at 232 deg c ti-base alloys were best. Carbon steel and the low-alloy steels are unsatisfactory for high-temperature, high- salinity brines.