The mechanisms by which Pteris vittata (L.) hyperaccumulates arsenic (As) have not been fully elucidated. To investigate how P. vittata tolerates high concentrations of arsenite, we compared the toxicities of various As compounds to P. vittata and Arabidopsis thaliana (L.). The phytotoxicities of As species were found to be in the order of arsenite > arsenate > dimethylarsinic acid (DMAA) in A. thaliana, and in the order of DMAA > arsenate > arsenite in P. vittata. P. vittata calli displayed a weaker ability to absorb arsenite than arsenate. These results demonstrate that P. vittata possesses mechanisms of As accumulation and detoxification.