An in-depth understanding of the biology of animals will require the generation of genomics resources from organisms from all phyla in the metazoan phylogenetic tree. Such resources will ideally include complete genome sequences and comprehensive EST (expressed sequence tag) datasets for each species of interest. Of particular interest in this regard are animals in the early diverging non-bilaterian phyla Porifera, Placozoa, Cnidaria, and Ctenophora. Publications describing the results from the use of genomics approaches in these phyla have only recently begun to appear (Kortschak et al., 2003; Yang et al., 2003; Steele et al., 2004). Issues to be considered here include choosing the basal metazoan species to examine with genomics approaches, the relative advantages and disadvantages of genome sequencing versus EST projects, and the resources and infrastructure required to carry out such projects successfully.