We formerly released the porcine expressed sequence tag (EST) database Pig EST Data Explorer (PEDE; http://pede.dna.affrc.go.jp/), which comprised 68,076 high-quality ESTs obtained by using full-length-enriched cDNA libraries derived from seven tissues. We have added eight tissues and cell types to the EST analysis and have integrated 94,555 additional high-quality ESTs into the database. We also fully sequenced the inserts of 10,147 of the cDNA clones that had undergone EST analysis; the sequences and annotation of the cDNA clones were stored in the database. Further, we constructed an interface that can be used to perform various searches in the database. The PEDE database is the primary resource of expressed pig genes that are supported by full-length cDNA sequences. This resource not only enables us to pick cDNA clones of interest for a particular analysis, but it also confirms and thus contributes to the sequencing integrity of the pig genome, which is now being compiled by an international consortium (http://www.piggenome.org/). PEDE has therefore evolved into what we now call 'Pig Expression Data Explorer'.