Development of new diagnostics tools, therapeutic devices and drugs are increasingly supported by collection and access to clinical, research and so called Real World Data (RWD). Processing of personal data may fall under various lawful grounds such as consent, public interest or legitimate interest, and should be in compliance with the principles of data protection including “lawfulness, fairness and transparency”. Regardless of what is considered as the lawful basis for processing data, the principle of transparency in data protection requires data controllers to provide data subjects with adequate information about various aspects of processing. However, the questions remain about the best practices in communication of relevant information to the patients and the individuals in order to both fulfill legal requirements and meet the expectations of data subjects in this regard. In this research project we aim to study the associated ethical, legal and technical challenges regarding transparency in processing health data, and to assess the adequacy of the relevant policies and mechanisms. Based on the results of this project we aim to develop recommendations to foster transparency around processing of health data for public and private scientific research.