Recently, the importance of observational clinical studies utilizing real world data (RWD) is highlighted. In Japan, so far large scale medical databases including claims data, prescription data, and DPC data have been utilized for the clinical epidemiology and pharmacoepidemiology studies, however, outcomes evaluation has been limited due to lacking of laboratory data. Therefore, starting from 2015, we are currently developing large scale electrical medical record (EMR)-derived database in Japan for the clinical epidemiology studies. We also focus on the development of the health checkup databases of newborn, infant, and children population, under the contract with more than 140 Japanese local city governments. These activities and the future opportunities for clinical research and preventive medicine will be discussed.