Nuclear and non-nuclear applications of cineradiography are reviewed, with emphasis on fuel-motion diagnostic instrumentation that is used for in-pile nuclear-reactor safety studies. The primary instrument for this purpose has been the fast-neutron hodoscope, which achieves quantitative monitoring of time, location, mass, and velocity of fuel movement under the difficult conditions associated with experiments in transient reactors. Nominal 1-ms, 0.1-g, 1-mm resolution have been accomplished during reactor transients of over 104 in power. Although alternative diagnostic devices—such as coded apertures, flash radiography, and pinhole imaging—have been developed, they have not matched the performance of the hodoscope; the evaluation of the relevant parameters appears in the paper. Because discriminating detectors can be placed in tandem in hodoscope channels, other test material constituents—such as cladding steel and sodium coolant—can be dynamically distinguished. Material-motion diagnostic systems can also be used for time-integrated radiography and direct time- and space-resolved fuel-pin power monitoring. High-resolution diagnostic systems are now operating at two reactors, and studies and tests have been carried out for application to several others.