Nanotechnology is a rapidly expanding and advancing field of research that has already yielded a variety of commercially available products including cosmetics, suntan lotions, paints, self cleaning windows and stain resistant clothing. The Royal Society and the Royal Academy of Engineering in their recent report ‘Nanotechnology and nanoscience: opportunities and uncertainties’ (http://www.nanotec.org.uk/finalReport.htm) concluded that nanotechnology is likely to have ‘huge potential’. While this report indicated that ‘many applications of nanotechnology pose no new health or safety risks’, it also recognised that the health, safety and environmental hazards of nanoparticles (diameter less than 100nm) and nanotubes requires investigation. A significant body of data exists regarding the toxicological effects of nanoparticles (also termed ultrafine particles) in mammalian systems, particularly with respect to the lungs and cardiovascular system. Such studies suggest that smaller particles, with a larger surface area per unit mass, are more potent at inducing oxidative stress and inflammation leading to adverse health effects. However, very few papers have been published regarding the effects of nanoparticles on other phyla such as micro-organisms, invertebrates and vertebrates from terrestrial and aquatic habitats. Since nanoparticles from both domestic and industrial products will be released into the environment, eg. wastewater, it is essential to investigate the impact on such species and the ecosystem. This presentation will aim to discuss how existing knowledge regarding the mammalian toxicology of nanoparticles could be used to generate an effective, efficient and focused strategy for testing the ecotoxicolgy of nanoparticles.