The Organization for Economic Cooperation and Development (OECD) posted on September 9, 2013, a final report entitled Co-Operation on Risk Assessment: Prioritisation of Important Issues on Risk Assessment of Manufactured Nanomaterials. This document follows on a report published by the Working Party on Manufactured Nanomaterials (WPMN) entitled Important Issues on Risk Assessment of Manufactured Nanomaterials, which identified a range of issues that the WPMN considered important in risk assessment and that should be addressed in the future. Because not all of these issues could be considered at the same time, WPMN circulated a survey to identify those issues for which further guidance should be developed as a priority. This document summarizes the survey results, the methodologies used to analyze the survey, and the identified priorities. These priorities will be the primary focus of projects pertaining to approaches for risk assessments of manufactured nanomaterials. On September 10, 2013, OECD posted a report entitled Environmentally Sustainable Use of Manufactured Nanomaterials, which presents the report of the September 14, 2011, workshop on the environmentally sustainable use of manufactured nanomaterials. The report includes a number of conclusions relevant for current and future OECD activities, especially those focused on life-cycle assessment (LCA) and nanomaterials, including: (1) basic structure and characteristics of LCA; (2) LCA application to nanomaterials at the research, scale-up, regulation, and market level; and (3) LCA application on nanomaterials data availability, reliability, comparability, and its generation.