Publisher Summary This chapter reviews the information that biologists interested in nuclear receptors can get by using a computer, including general resources and those specialized in nuclear receptors, whether for accessing data or analyzing it. Nuclear hormone receptors are one of the most abundant classes of transcriptional regulators in metazoans (animals), in which they regulate functions as diverse as reproduction, development, metabolism, or homeostasis. They function as ligand-activated transcription factors, thus, providing a direct link between signaling molecules that control these processes and transcriptional responses. The importance of nuclear receptors has prompted the accumulation of rapidly increasing data from a great diversity of fields of research—sequences, expression patterns, 3D structures, protein–protein interactions, target genes, physiological roles, mutations, etc. This has in turn highlighted the need for good bioinformatics. The present of bioinformatics for nuclear receptors is mostly composed of three specialized databases— The Nuclear Receptor Resource (NRR), NucleaRDB, and NUREBASE. which allow faster and easier access to relevant information, and more or less easy data-mining from other sources. The future lies in ‘‘postgenomic’’ bioinformatics: through the integration of experimental data into bioinformatic bases and the analysis of nonannotated sequences. This answer will in some cases be no more than a lead toward new experimental work and in others hopefully is almost definitive, as can already be done for phylogenies for example.