The introduction in Japan of New GCP regulations, as well as the internationalization of clinical trials under the ICH process (International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use), has meant that the system is now faced with a number of serious challenges. This is shown by the dramatic decrease in registration of new drugs. Identifying the actors in the new context is essential. We shall first define precisely what is the Regulatory Authority in Japan, and which are the Regulatory Requirements to be fulfilled. We shall then describe the new process for evaluation of foreign clinical data. One of the major issues will be to determine in which cases a complete clinical data package will be sufficient to support regulatory submission, and in which cases additional clinical studies or bridging studies, and what kind of bridging studies will be required.