Abstract The extreme light infrastructure (ELI) is emerging as a state-of-the-art facility providing international users with open access to ultrashort laser-driven particle bunches, ranging from a few femtoseconds to a few nanoseconds, for advanced radiobiology studies. ELI offers femtosecond-class laser pulses and ultrafast ionizing radiation characterized by extremely high instantaneous dose rates (107–1012 Gy/s). The versatility of ELI’s cutting-edge technologies enables the generation of high repetition rate (1 Hz–1 kHz) secondary sources (protons, ions, electrons, and neutrons) with energies from a few MeV to several hundred MeV, achieved over sub-millimetre to millimetre-scale acceleration lengths, along with fundamental research in the field of ultrahigh intensity laser-matter interaction based on the use of the highest peak power laser pulses available worldwide. Harnessing these laser-driven particle sources for radiobiology and medical research demands a coordinated international effort, with a strong focus on advancing scientific instrumentation and refining experimental methodologies to support progress in ultrafast laser-driven radiation biology. This roadmap underscores the need for systematically designed experiments across ELI facilities, supported by preparatory research at users’ home laboratories, alongside the ongoing development of instrumentation and infrastructure. These efforts are critical to rigorously assess and validate the therapeutic potential of these novel sources, paving the way for a transformative shift in radiation biology and medicine.