Chapter 4 presents the use of neutron imaging in the field of nuclear materials. As a non-destructive technique with high sensitivity to hydrogen and intrinsically provided capability of investigation of (highly-)activated specimens, neutron imaging provides a very suitable characterization tool for a large number of characterization tasks that can be hardly performed by other probes. The chapter is divided into subchapters on nuclear fuels, structural materials in nuclear applications, applications in reactor cooling and safety and nuclear waste studies.