A plant useful for phytoremediation has first to grow in the presence of the target pollutant without being harmed. The plant must not only be resistant to the pollutant, but must also be able to remove it from the environment and transform it into nontoxic metabolites or end products. Differences in the ability of various plant species to accumulate and metabolize particular pollutants do exist, indicating that in choosing the most appropriate species in the development of any phytoremediation process, natural biodiversity should be better explored and exploited. Plant taxonomy and phytochemistry can help in the exploitation of biochemical specificities of plants that produce natural chemicals with structures similar to xenobiotic compounds. In the case of atrazine, however, numerous results obtained for agronomical purposes are extremely useful in choosing the most appropriate families or genera for phytoremediation.