The CCRI(II) has formed a new Task Group to support the increasing use of mass spectrometry in radionuclide measurement applications across areas including nuclear decommissioning, environmental monitoring, and nuclear forensics. The Task Group is exploring current and potential roles for mass spectrometry in radionuclide metrology, including the identification of priority radionuclides, development of methods, instrumentation, standards, and relevant reference materials, as well as identifying the best approaches for the exchange of information. Collaborations with other communities are establishing where radionuclide measurement by mass spectrometry can add value, including earth and climate science, food safety, environmental monitoring, and emergency response.