The spatial distribution of soil microarthropods in soybean fields was investigated by use of a modified Tullgren extractor. Blocks of soil were extracted over a grid of collection cells from which microarthropod aggregations could be identified and measured. Aggregations in conventionally tilled soybeans were smaller than those in no-tillage soybeans, and had less influence on population distributions. Population size was highly correlated with the area of soil microarthropod aggregations.