Crop rotation is a common management practice that has been recognized as a proven method that increases crop yields. This study evaluated methods for analyzing a long-term crop rotation experiment that investigated continuous, two-, three-, and four-crop rotations over a five-year cycle. The yield effects on the first phase of corn (Zea mays L.) in a rotation were examined from data collected since 1966 at Lancaster, WI. Corn yields increased 21% over the duration of this experiment. During the last 20 years, continuous corn was consistently the lowest yielding treatment; yielding from 5.8 to 31% less than other rotation treatments. Continuous corn yields were the most variable compared to other rotation treatments. Crop rotations that contain three or four different crops showed a greater rate of yield increase (35 and 36%, respectively) than did continuous cropping or rotations with two crops (20 and 25%, respectively). Greatest yields on the first phase of corn were measured in diverse rotations involving three or more crops, followed by two-crop rotations followed by continuous monoculture.