MatISSE/JPNM workshop on cross-cutting issues in structural materials R&D for future energy systems took place in Institute for Energy and Transport, Petten, The Netherlands, on 25, 26 November 2015.The purpose of this Workshop was to discuss the status of structural materials R&D for future energy systems and particularly to identify common topics and sharing knowledge between different technologies such as renewables (wind, photovoltaics, etc.), nuclear and "clean" fossil fuel technologies. The collaboration on materials qualification and development across low carbon energy technologies on cross-cutting issues is a way to accelerate the energy system transformation towards the highest possible standards of safety, cost reduction and increased efficiency. Two-day workshop addressed four main cross-cutting issues, High temperature applications, Compatibility with liquid metals, Design Codes, Advanced steels. During the workshop more than 23 oral presentation have been presented to more than 70 participants. Among others also a topic of structural materials for GFR-ALLEGRO has been addressed in the presentation Candidate materials for GFR concept ALLEGRO and R&D related activities structural materials R&D.