Nuclear hyperfine interaction investigations of radiation damage are reviewed. Emphasis is laid on implantation experiments, where nuclear radiation emitted by the implanted probes conveys information about defect structure and its annealing. Various nuclear hfi techniques are briefly discussed and their merits and limitations for radiation damage studies are compared. It is pointed out how defect rearrangements that occur in various annealing stages can be recognized from their influence on hyperfine interactions. Recent experiments that provide more than qualitative information about radiation damage are discussed in some detail. Where possible, hfi and channeling results are compared. The importance of extending the implantation dose range to lower doses so as to avoid overlap effects of damage cascades is emphasized.