Previously published analyses of copper objects from Argentina (18), Bolivia (4), and Peru (16) are critically examined. New analyses, made by gravimetric and spectrographic methods, are given for 14 objects from Peru. It is concluded that 1) native copper was used in only a small proportion of ancient South American copper objects, 2) a variety of ores was used, 3) most objects are arsenical copper, some of which were probably manufactured intentionally. Although some 575 analyses of ancient copper and bronze objects from South America have been published, most of them are inadequate for various reasons.