Characterising spent nuclear fuel (SNF) and radioactive waste is essential for ensuring safe and efficient interim and final disposal. Precise knowledge of waste properties, including radionuclide composition, decay heat, reactivity, gamma-ray and neutron emission, allows for informed decision-making in storage, transport and disposal. Proper characterisation reduces uncertainties in safety assessments and helps optimise SNF and waste management. This session would explore advancements in characterisation methods and their critical role in the SNF and waste management.