An antioxidant is a molecule that can prevent free radicals from causing damages in organisms. The increasing studies on antioxidants calls for a specialized database that is not readily available yet. To this end, in the present study, the Antioxidant Database (AOD) was developed to help researchers understand and reveal the biological functions of antioxidant proteins. AOD is freely available at http://lin.uestc.edu.cn/AODdatabase/index.aspx . The current release of AOD consists of 710 antioxidant proteins. Information including taxonomy, source organism, subcellular location, gene ontology, catalytic activity and function of antioxidant proteins are all extracted from UniProtKB/Swiss-Prot and captured in AOD. In addition, two web-based tools for performing sequence similarity search and computationally identification of antioxidants were also integrated in AOD. We believe that AOD will greatly facilitate the researches on antioxidants.