Toxin-antitoxin (TA) pairs are genetic modules commonly found in bacteria. They usually consist of a toxin and an antitoxin, which act together to regulate bacterial growth, stress response, and maintenance of genetic stability. To date, eight type TA systems have been reported. TA pairs are found to be passengers on almost all kinds of Mobile Genetic Elements (MGEs), such as plasmids, genomic islands and prophages which allow these systems to rapidly disseminate through bacterial communities by horizontal transfer. The aim of this TADB database is to create and maintain a resource of all currently available TA loci data from experimental data, and investigate the relationships of TA loci and MGEs.