A systematic study of fuel motion in TREAT tests related to liquid-metal fast breeder reactor (LMFBR) safety has been conducted for recent experiments containing typical LMFBR fuel Net axial fuel motion is characterized by changes in fuel reactivity worth using representative LMFBR fuel-worth distributions. Fuel-motion data from these experiments, when converted to changes in equivalent fuel worth, permit interpretations based on the experimental results to be related to specific LMFBR safety issues. Verification of fuel-motion-model predictions in accident-analysis codes can also be greatly simplified by comparisons with the experimental results using the equivalent fuel-worth changes as the principal figure of merit.