Earthworm populations usually increase as conventional tillage fields are placed under conservation tillage management. We sought to record earthworm response to tillage practices and crop type on farms of the Palouse region. During the Spring and early Summer of 2002 and 2003 we sampled earthworms and earthworm cocoons from 24 fields managed with conventional and conservation tillage. Fields were under a pea-wheat-barley rotation with half of the fields planted to peas and half planted to wheat. Soil pits were dug to a depth of 50cm along transects with either northeast or southwest aspect, and earthworms and cocoons were removed by sieving. Soil was sampled in 10cm depth increments and analyzed for pH and total C and N. No relationships between tillage practices and pH with depth were found. However, total C at 5cm was higher in conservation tillage fields and decreased at a lesser rate with depth than in conventionally tilled fields. This increased C near the surface might play a key role in earthworm survival and reproduction. Comparing conservation tillage with conventional tillage, roughly 2 times as many earthworms and 2.5 times as many cocoons were found in conservation tillage fields. More earthworms and cocoons were found in fields planted to peas than to wheat, presumably due to the increased residue load from the previous wheat crop. Crop effects were especially evident in conservation tillage peas where cocoons outnumbered earthworms. A higher ratio of cocoons to earthworms suggests an increasing, vibrant population. Conservation tillage wheat crops following peas exhibited a much lower ratio suggesting a declining or stationary earthworm population. Earthworm populations are likely affected by residue from the previous year's crop and management factors including fertilizer and pesticide use during the previous year.