CAREX was designed to promote prevention through raising awareness and targeting high risk populations. CAREX was designed as a system that could be applied to other countries and its use internationally has been broadened to include national burden of occupational cancer projects in specific countries, as well as in the Global Burden of Disease project. CAREX Canada is based on a combination of occupation and industry and, when possible, estimates level of exposure as well as prevalence. This has allowed it application as a job exposure matrix for use in other applications. The Occupational Cancer Research Centre, in collaboration with its partners, has used it successfully with both its Occupational Disease Surveillance System and Burden of Occupational Cancer projects. In applying CAREX to other applications, it is important to recognise that it is based on the concept of hazard rather than risk, which is appropriate for primary prevention. Thus, in burden of disease projects it is important to choose relative risks that are appropriate for exposure based on broadly defined groups. In applications to disease surveillance, prevalence rates less than 100% can lead to non-differential misclassification and low levels of exposure can mute associations, especially when added to the existing limitations of data typically used for surveillance. Addressing these limitations can facilitate the successful application of CAREX in wider applications.