The problems of water shortages and lack of access to safe drinking water have been and will continue to grow as major global problems. To alleviate these problems, water purification technologies are being updated. Recent years have witnessed impressive breakthroughs towards practical application of nanostructured materials such as Carbon Nanotubes (CNTs) in the field of water purification owing to their unique thermal, electrical and mechanical properties. These nanoscale structures need to be arranged into well-defined configurations in order to build integrated systems with high efficiency (the nanotubes being reusable, whereas the traditional membranes foul easily and require frequent replacements), high flux (owing to the hydrophobic super smooth inner surface of nanotubes), and with improvements in chemical selectivity (through suitable chemical functionalisation of the CNTs), so that the idea of using CNTs in separation technology can be made realistic and the potential benefits of practical application of these unique materials can be exploited. This paper assesses the CNTs as an emerging technology in water purification system, particularly with respect to its potential for the removal of arsenic, fluoride, heavy metals and toxic organic components. Copyright © 2008 Inderscience Enterprises Ltd.