When Directive 2010/84/EC introduced the principle of EU PSURs single assessment (PSUSA procedure) for substances authorised in more than one member state, a step-wise approach was taken to the full implementation of new PSUR procedures; the EMA Management Board decided that the implementation of the new procedure for substances only included in NAPs should have started after 2013 and that the PSUR work sharing project would continue in its established framework until the full application of the single assessment procedure for NAPs, that was subsequently introduced for PSURs having DLPs after 31st August 2014. The PSUR Work Sharing list was therefore updated, merged with some substances from the synchronisation list and renamed ‘List of substances under PSUR Work Sharing scheme and other substances contained in Nationally Authorised Products with DLP synchronised’. Such active substances and combinations of active substances originally included in the List of Union reference dates and frequency of submission of Periodic Safety Update Reports (also called EURD list) with DLPs between 1 April 2013 and 31 August 2014, were removed from the EURD list and transferred to the new PSUR work sharing list until they would follow the EU single assessment procedure of PSURs. MAHs were strongly advised to submit their PSURs in accordance with the List of substances under PSUR Work Sharing scheme and other substances contained in Nationally Authorised Products (NAPs) with DLP synchronised which was legally interpreted as a «coordinated» national request addressed to MAHs in accordance with Article 107c (2) of Directive 2001/83/EC as amended. With the introduction of the single PSUR assessment for NAPs at the end of 2014, the list was gradually superseded by the EURD list. The PSUR Work Sharing Project was officially declared concluded in December 2019. More than 1.500 work sharing procedures were finalised and allowed a more than significant reduction of the administrative burden, both from NCAs and MAHs side. The PSUR Work Sharing Project represented a key example of successful collaboration between NCAs and industry, on a voluntary basis, to manage a large volume of work and streamline the process of delivering public health outcomes, with a better allocation of resources. It has significantly contributed to the harmonization of safety information for products containing the same active substances/combinations of active substances in Europe. Finally, the PSUR Work Sharing Project represented the fundamental exercise that gave birth to the PSUSA procedure established with Directive 2010/84/EC.