The medaka (Oryzias latipes), a small freshwater teleost from Japon and South-East Asia, is an increasingly popular vertebrate model in biology. However, the anatomical data available on this species are scarce, or difficult to access, a relative lack that is ail the more regrettable tor the central nervous System (CNS), This atlas is composed of 55 serial transverse sections (microphotographs and mirror-image drawings with named structures - using up-to-date nomenclature) of adult medaka CNS, along with 7 horizontal and 7 sagittal sections. Small aquarium teleosts (medaka and zebrafish) are mostly used today for developmental genetic analysis. In this context, this atlas is primarily intended for researchers with an interest in identification of CNS structures where newly cloned genes are expressed. Developmental and/or evolutionary neurobiologists should be especially interested by comparisons of expression patterns with relatively close species (the zebrafish), and distant ones (the rat or the mouse)