OBJECTIVES: Increasingly regulators and payers world-wide are seeking real world data (RWD) to inform decisions on access to new medicines. While the ISPOR International Digest of Databases is a valuable resource to facilitate the access of health outcome researchers to RWD, a limitation is that it depends on database providers to submit database information to ISPOR. In this research we aim to build on this initiative by searching specifically in the therapeutic areas of oncology, cardiology and endocrinology for databases that can assist researchers to identify suitable databases in Europe and test whether they can answer relevant research questions.  METHODS: The search was limited to the United Kingdom, Germany, France and the Netherlands using generalized research questions. Review of the existing initiatives supplemented with interviews was conducted to set the final framework of the research and refine the attributes relevant to the therapeutic areas. Secondary research was conducted to identify real world databases not captured previously. The database holders were contacted by phone and/or email to obtain further information on the specifics of the databases. RESULTS: Five previous initiatives including ISPOR were identified and reviewed. A total of 122 databases were identified and assessed. Of these, 86 databases (~70%) were not mentioned in any of the previous initiatives. Oncology databases formed the majority of the databases (57), followed by endocrinology (14) and cardiology (13with the other 38 databases covered multiple therapeutic areas. Information was gathered on general details, disease specific outcome measures, as well as technical details. CONCLUSIONS: Our non-exhaustive research has shown that databases with the potential to answer these hypothetical research questions do exist in all countries. This research helps identify potential sources for RWD analysis, but in practice a well-defined research question is needed to assess the true suitability of the database.