In order to improve the conditions for clinical research in Europe and to stimulate multinational clinical trials, CTIS - clinical trial information system - has been developed. It is a platform that is ONE single entrance to the clinical trial application and includes both the drug application and ethical approval. Several years of preparatory work and a one-year transition period have ended and from February 1, 2023 CTIS has been put into use and is mandatory to use. CTIS has been built and improved in close cooperation with users (industry and academia) and national pharmaceutical authorities and EMA, the European Medicines Agency.