This article summarizes the zooarchaeological record of Archaic period occupations of Idaho's Snake River Plain. The record suggests an early and continuing use of deer, elk, and bison with an increasing use of rabbits and small mammals during the Middle Archaic (5000-2000 BP). Archaic period prey choice reflects considerable evenness over time and across the Plain. The Late Archaic period (2000-150 BP) is, however, characterized by an increase in the ubiquity of fish and artiodactyl associated with the emergence of modern conditions reflecting greater aridity. Through diet breadth appears to have narrowed and broadened by local potentialities, there is generally little evidence of resource intensification or depression.