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As part of work to prioritize potentially carcinogenic agents, national health security agencies, governments, and other organizations, as well as researchers, are implementing various prioritization methods. The use of score calculations has been adopted in a number of published works, in order to classify potentially carcinogenic agents. Hazard scores for potential carcinogens are based mainly on the various existing classifications of their carcinogenicity. Based on the expert assessments carried out by various authorities and research teams, equivalences have been achieved between the various non-regulatory classifications and the classification resulting from the European Classification, Labeling, Packaging (CLP) regulation, without always leading to the same results. Establishing formal equivalences is not possible because of the many factors involved, from the outset right through to the end of the process, in assessing potentially carcinogenic agents. However, because of the similarities between the classification systems, statistical or more detailed equivalences according to categories can be established. The objective of this analysis is, on the one hand, to identify the common points and differences between the classification criteria as well as the other parameters that may lead to classification discrepancies and, on the other, to propose equivalences between the European CLP classification and other classification systems.