Channels made by deep-burrowing (anecic) earthworms are known to strongly affect soil water flow and increase the leaching risk of agricultural pollutants. A classification tree that predicts the abundance of the anecic earthworm Lumbricus terrestris L. from readily available survey information (land use, management practices, and soil texture) was derived from literature data (n = 86). The most important factors favoring L. terrestris were perennial land use, no-till arable cropping, organic additions (i.e., manure), and medium-textured soil. The classification scheme correctly predicted earthworm abundance for 71% of the studies in the database. Among other potential applications, the classification tree could be used to identify areas at risk from groundwater pollution in agricultural landscapes and to support catchment- and regional-scale models of contaminant leaching in the vadose zone.