Selenoproteins are a diverse group of proteins/nusually misidentified and misannotated in sequence/ndatabases. The presence of an in-frame UGA (stop)/ncodon in the coding sequence of selenoprotein/ngenes precludes their identification and correct/nannotation. The in-frame UGA codons are recoded/nto cotranslationally incorporate selenocysteine,/na rare selenium-containing amino acid. The development/nof ad hoc experimental and, more recently,/ncomputational approaches have allowed the efficient/nidentification and characterization of the/nselenoproteomes of a growing number of species./nToday, dozens of selenoprotein families have been/ndescribed and more are being discovered in recently/nsequenced species, but the correct genomic annotation/nis not available for the majority of these/ngenes. SelenoDB is a long-term project that aims to/nprovide, through the collaborative effort of experimental/nand computational researchers, automatic/nand manually curated annotations of selenoprotein/ngenes, proteins and SECIS elements. Version 1.0 of/nthe database includes an initial set of eukaryotic/ngenomic annotations, with special emphasis on the/nhuman selenoproteome, for immediate inspection/nby selenium researchers or incorporation into more/ngeneral databases. SelenoDB is freely available at/nhttp://www.selenodb.org.