In Italy, the National Register on Occupational Exposure to Carcinogens (SIREP) is established pursuant to article 243 of Legislative Decree 81/2008 and is aimed to collect information on the exposure of workers to carcinogens transmitted by employers. The aim of this study is to assess its level of implementation comparing prevailing carcinogens reported in SIREP with the monitoring of risks in the workplace evidenced by the International Agency for Research on Cancer (IARC). The data reported in the SIREP have been integrated with IARC and the database on carcinogenic risk in the workplace named MATline in order to build a matrix containing the carcinogens classified according to the IARC (Group 1 and 2A agents) and to a semi-quantitative indicator of risk level (High or Low) calculated upon the number of exposures reported in SIREP. The matrix contains the following data: carcinogens, economic sector (NACE Rev2 coding) and cancer sites. The comparison between SIREP and IARC evidence allowed us to highlight situations with a high risk of carcinogenicity and to address appropriate actions of prevention to contain the risks of exposure to carcinogenic substances.