G-TwYST will execute rat feeding trials with GM maize NK 603 based on OECD Test Guidelines and according to EFSA considerations. In the case of maize NK603 two 90-day and a combined 2-year chronic toxicity/carcinogenicity study will be performed. By combining the results of the G-TwYST project with those of the GRACE project (90-day and 1-year study with maize MON810) it will be possible for the first time to describe the potential medium term and long term toxic effects of the two above-mentioned events.Partners will strictly comply with international standards and norms concerning feeding trials and closely collaborate with EFSA. Feeding stuff used in the trials will be produced according to the principles of good agricultural practice. The project will analyse and report the results of the feeding trials and develop recommendations on the scientific justification and added value of long-term feeding trials for GMO risk assessment.The project will ensure scientific excellence, independence and transparency of both the research process and the results. Transparency and accessibility of project plans and results is a key characteristic of the project and will be ensured by establishing a project website and by using an open access database set up by GRACE as information hubs. Results will be published as open access journal papers. Dedicated engagement, communication, and dissemination activities will target scientists, policy makers and a broad range of stakeholders. Participatory steps will be included in the planning as well as in the interpretation/conclusion phase. Moreover, the views of risk assessment and regulatory bodies as well as wider societal issues will also be taken into consideration.The results of the project will enable risk managers drawing conclusions with regard to framework of the currently applicable GM food/feed risk assessment requirements and procedures in the EU.