The implementation of the EU Directive on non-financial information determines the transition from a voluntary to a mandatory disclosure setting. This paper is a first attempt to investigate if this transition influences the value relevance of non-financial information, which relates to the environmental, social and governance disclosure (ESG) requirements of the Directive. Italy provides an interesting setting as non-financial information was generally voluntary before the Directive, which was implemented with the Italian Legislative Decree 254/2016. To this extent, we examine the non-financial, environmental and social disclosure practices of 231 Italian listed firms in the pre-(2016) and post-(2017) Legislative Decree application. Our results do not show any relevant increase of such disclosures after the Legislative Decree application, as Italian listed firms limit such disclosure to a minimum requirement. Further, this finding is confirmed also for those firms voluntarily providing a non-financial report (sustainability or integrated report) before the Legislative Decree application. Our regression analysis shows that accounting numbers are associated with share prices, while non-financial, environmental and social information are not value-relevant with reference to the pre-and post-Legislative Decree application. This means that the non-financial, environmental and social information beyond the financial accounting information do not explain any incremental value-relevant information to investors in the non-financial mandatory disclosure setting required by the new regulation. Our results enrich previous evidence concerning the value relevance of non-financial and ESG disclosure mainly focused on Anglo-Saxon contexts.