Contamination of soil with arsenic is one of the major causes of the presence of arsenic in drinking water. To understand and manage the risk posed by soil arsenic it is essential to know how arsenic is taken up by roots and metabolized in plants. Some plant species exhibit phenotypic variation in response to arsenic species, which helps to understand the toxicity of arsenic and the way in which plants have evolved arsenic resistance. A number of plants have been identified as hyperaccumulators in the phytoextraction of a variety of metals, and some have been used in field applications. This paper reviews major processes that can affect the fate of arsenic in the soil – rhizosphere – plant system.