Data used for the assessment modelling of the Canadian concept for disposal of nuclear fuel waste is mainly based on observations from short-term laboratory and field experiments, although it must apply to periods of 10,000 to one million years. Natural analogs can provide useful data and a qualitative illustration of the interaction of processes and materials in complex natural systems. This report reviews the available natural analog information used in support of the Canadian concept, with particular emphasis on the disposal of used CANDU fuel. The report gives a definition of natural analogs and an overview of the various types of analogs and analog studies; describes the main components of the disposal system, including the vault, the geosphere, and the biosphere, and gives specific examples for each; and describes several comprehensive natural systems that contain a number of features and processes similar to the disposal concept and that are under study by other countries as part of their waste disposal management programs.