Abstract: The ESTree db represents a collection of Prunus persica expressed sequenced tags (ESTs) and is intended as a resource for peach functional genomics. With this aim, the db has been structured to be a repository of information and links related to the sequences and to provide a userfriendly interface to allow easy querying of all the db fields. Within the month of March 2005 the third release of ESTree will be online and will include 18630 sequences, encompassing 8 libraries at different peach fruit developmental stages. A second version of the db, including only the 6155 sequences produced by the FPTP-CERSA group will also be online. The major data resources that are included in the ESTree db are: annotation both with BLASTx versus the NCBI nr database and with BLASTx versus the GO viridiplantae subset of sp-trembl; contig assembly and display; SNP analysis with AutoSNP and links to the KEGG metabolic pathways and the enzyme entries of NiceZyme (Expasy). Gene Ontology statistics are also presented both for the whole set of sequences that are included in the db and for library-specific subsets.