This discussion forum will provide an overview of the key challenges that face practitioners and data providers when undertaking LCA of nanotechnology and will present possible solutions. The opening session will outline the need for environmental assessment of nanotechnologies in light of growing interest in nanomaterials for consumer and industrial applications and prevailing concern for the potential environmental impacts of nanoparticle emissions. The possible role of LCA in guiding environmentally-responsible innovation for emerging nanotechnologies will then be discussed. The second session will focus on prospective modelling of nanotechnologies and will consider how uncertainty should be dealt with in LCA of emerging technologies. A key question to be addressed is whether or not lab-scale data can or should be used as a basis to assess the potential impacts of intended future plant-scale production and, if so, what methods could be applied. Case studies will be presented to provide insights into how these issues have been dealt with in reality. The third session will outline why and how existing LCIA models must be modified (in terms of fate, exposure, and toxicity modelling) to enable more representative evaluation of the potential impacts of nanoparticle/nanomaterial emissions. In the fourth and final session, the potential added values of combining LCA with risk assessment (RA) approaches will be discussed, highlighting the potential for enhancing our knowledge of how nanotechnologies affect the environment, human health, and society. This forum aims to provide a fertile ground for discussion between LCA researchers, practitioners and other people interested in the sustainable development of nanotechnologies.