Ovarian Kaleidoscope database (OKdb) is an online, searchable, public database containing text-based and DNA microarray data to facilitate research by ovarian researchers. Using key words and predetermined categories, users can search ovarian gene information based on gene function, cell type of expression, cellular localization, hormonal regulation, mutant phenotypes, chromosomal location, ligand-receptor relationship, and other criteria, either alone or in combination. For individual genes, users can access more than 10 extensive DNA microarray datasets to interrogate gene expression patterns in a development-specific and cell type-specific manner. All ligand and receptor genes expressed in the ovary are matched to facilitate investigation of paracrine/autocrine signaling. More than 3500 ovarian genes in the database are matched to 185 gene pathways in the Kyoto Encyclopedia of Genes and Genomes to allow for elucidation of gene interactions and relationships. In addition to >400 genes with infertility or subfertility phenotypes when mutated in mice or humans, the OKdb also lists ~50 and ~40 genes associated with polycystic ovarian syndrome and primary ovarian insufficiency, respectively. The expanding OKdb is updated weekly and allows submission of new genes by ovarian researchers to allow instant access to DNA microarray datasets for newly submitted genes. The present database is a virtual community for ovarian researchers and allows users to instantaneously provide their comments for individual gene pages based on an automated Web-discussion system. In the coming years, we will continue to add new features to serve the ovarian research community.