Life Sciences and Nano Sciences interact today mainly in two areas: in the evaluation of accidental health and environmental effects derived from engineered nanomaterials, and in development and biological/clinical evaluation of nanoparticles with intended biological effects for application in medicine and biotechnology. Growing contact between these initially widely separate fields has led to highly productive interactions catalysing both the accumulation of scientific knowledge and realisation of the full potential of nanotechnology. It is essential for producers, distributors, consumers and regulators that the safety of products containing nanomaterials can be certified with reliable, validated assays. Research efforts are under way to establish suitable test methods and to understand mechanisms potentially leading to a detrimental impact of nanomaterials on human health and on the environment. However, this important field still urgently lacks sufficient trained personnel. Scientists active in this area are usually mono-disciplinary biologists, chemists, physicists or engineers, who enjoy the challenges of interdisciplinary work, but face the obstacle of acquiring (or finding) expertise in the complimentary technology. The ITN “Nanotechnology: Training Of Experts in Safety” (NanoTOES) will establish a network of research projects working towards the refinement and standardisation of existing methods, will develop novel assays suitable for analysing the interaction of biological systems and nanomaterials, and will during this process provide interdisciplinary training to Early Stage Researchers (ESR) and Experienced Researchers (ER) working at the intersection of biosciences and nanosciences. A training network will be set up wherein young scientists shall undertake specific projects in which they apply techniques and expertise from medicine, immunology, biology, toxicology, biochemistry, chemistry, biophysics, physics, materials sciences, and engineering to address technical challenges directly related to nanotoxicology, and in which they interact with academic and industrial partners throughout Europe. Training in legal and regulatory aspects, communication, verification, and the practical application of results will be a major part of this ITN. A suite of methods developed and validated in the NanoTOES project shall have utility in characterising the biological effects of nanomaterials, including their impact on the environment, and will add significantly to our understanding of the biological actions of nanomaterials and their resultant effects on human health and the environment. Equally, the influence of biological entities (molecules, cells, tissues) on the properties of nanomaterials will be investigated. This aspect is crucial to understanding the properties of nanomaterials in organisms and in the environment, but nevertheless this issue has been so far not sufficiently explored. We need to understand the properties of nanomaterials as they are when they are in use or have been discarded, which involves both a close observation of contaminants and of modifications of nanomaterials that are induced by proteins and other biological compounds. These timely and novel studies, performed by the fellows trained by NanoTOES, will be disseminated through European and National research programs, as well as through peer- communication with laboratories active in the field. The experience gained during their scientific training will equip the NanoTOES fellows to pursue careers in the field of nanotechnology and nanotoxicology, an outcome that will address the pressing need for such trained personnel, and enable European science in this area to remain globally competitive.