Since 2004, the process of evaluation and approval review of new drugs and new medical devices in Japan has been undertaken by the Pharmaceutical and Medical Devices Agency (PMDA), which was established in the same year. PMDA conducts timely evaluation in order to ensure that public and healthcare professionals gain the maximun benefit of advanced, safe drugs and medical devices. The Japanese government has decided to reduce the "drug lag" by 2.5 years until fiscal year (FY) 2011. To achieve this goal, PMDA has undertaken some measures such as including increasing the number of reviewers reducing the period of development by significantly improving consultation services, developing guidance toward the introduction of prior assessment consultation system. Moreover, to improve of post-marketing safety measures, PMDA established a support system incorporating the data mining method. It is the PMDA's responsibility to put in its best efforts towards evaluateing various conflicting issues and appropriately balance them by assessing risks and benefits on the basis of the present scientific knowledge, in a manner that is most beneficial for public interest. Regulatory science thus provides a scientific basis for regulatory decisions. We strive to promote the regulatory science by establishing communication with external scientists and providing enhanced training to improve the staff's capability to apply regulatory science.