Technical Abstract: Genomics can be used to solve many problems associated with the management of weeds. New target sites for herbicides have been discovered through functional genomic approaches to determine gene function. Modes of action of herbicides can be clarified or discovered by transcriptome analysis. Understanding crop/weed competition and allelopathy can be improved by gene chip technology to determine transcriptome responses to these processes. Genomic methods can be used to predict the propensity of weed species for evolving resistance to herbicides. These are examples of the many weed problems discussed in this review that can be better understood or solved with the help of genomics.