The overall objective of this study was to identify common patterns in thespatial distribution of the major weed species present in the corn-growingregion of central Spain, exploring the scale dependence of these patternsand the possible associations or dissociations between individual species.Weed density was assessed in 16 commercial fields using digital imagesacquired in a 9-m by 9-m sampling grid. A set of six species was found inall the fields: black nightshade, common cocklebur, fierce thornapple,johnsongrass, purple nutsedge, and velvetleaf. Spatial analysis by distanceindices and inverse distance weighting interpolation methods were performedto create weed distribution maps. The results showed aggregated spatialdistribution patterns for all individual species regardless their lifecycle, annual or perennial. Some associations and dissociations amongspecies were found in the analysis of interactions. Nevertheless, thespatial patterns of co-occurrence of weed species were field-specific andtherefore cannot be considered general patterns of weed co-occurrence. Inorder to explore the scale dependence of these results, an additional studywas conducted in an experimental field located in the same area using a1.0-m by 0.75-m sampling grid. Although this resolution allowed for a betterdefinition of the positions of the weed patches and weed-free gaps, theresults obtained revealed similar patterns to those observed with a coarsersampling resolution.