Early market access of health products is associated with a larger number of requests for information by the health authorities. Compared with these expectations, the growing expansion of health databases represents an opportunity for responding to questions raised by the authorities. The computerised nature of the health system provides numerous sources of data, and first and foremost medical/administrative databases such as the French National Inter-Scheme Health Insurance Information System (SNIIRAM) database. These databases, although developed for other purposes, have already been used for many years with regard to post-registration studies (PRS). The use thereof will continue to increase with the recent creation of the French National Health Data System (SNDS [2016 health system reform law]). At the same time, other databases are available in France, offering an illustration of “product use under actual practice conditions” by patients and health professionals (cohorts, specific registries, data warehouses, etc.). Based on a preliminary analysis of requests for PRS, approximately two-thirds appeared to have found at least a partial response in existing databases. Using these databases has a number of disadvantages, but also numerous advantages, which are listed. In order to facilitate access and optimise their use, it seemed important to draw up recommendations aiming to facilitate these developments and guarantee the conditions for their technical validity. The recommendations drawn up notably include the need for measures aiming to promote the visibility of research conducted on databases in the field of PRS. Moreover, it seemed worthwhile to promote the interoperability of health data warehouses, to make it possible to match information originating from field studies with information originating from databases, and to develop and share algorithms aiming to identify criteria of interest (proxies). Methodological documents, such as the French National Authority for Health (HAS) recommendations on “Les études post-inscription sur les technologies de santé (médicaments, dispositifs médicaux et actes). Principes et méthodes” [Post-registration studies on health technologies (medicinal products, medical devices and procedures). Principles and methods] should be updated to incorporate these developments.