Hierarchical arrangements of transcription factors (TFs) into regulatory networks provide the information necessary to deploy genes with particular spatial and temporal patterns. The information for this is hardwired in the promoter regions of genes formed by cis-regulatory elements that bind specific TFs. The increasing availability of genome sequence information for Arabidopsis and other plants is making it possible to start to establish the regulatory networks that result in the expression of all plant genes. Our approach towards establishing the architecture of plant regulatory networks is being to identify immediate or direct targets for a set of Arabidopsis TFs and integrate this information into increasingly powerful bioinformatics resources, such as those developed as part of our AGRIS suite of databases and computational tools.