Reports on nine samples from well-dated prehistoric sites in the southwestern United States that have been radiocarbon dated in order to determine the accuracy of carbon-14 dates of corn. The results indicate that a normalized and calibrated carbon-14 date of corn is as accurate an estimate of the sample's age as is a carbon-14 date for any other material. This accuracy has implications not only for future selection of carbon-14 samples but also for interpretation of existing dates on corn and on other kinds of material.