The paper presents analysis of the legal and ethical issues surrounding establishment of the Latvian Healthcare Monitoring Datalink. The paper covers three interconnected issues in the context of the use of administrative health data for research purposes – anonymization of data, concept of ‘public interest’ and involvement of research ethics committees. The analysis has been put into broader context of interaction between General Data Protection Regulation (GDPR), national legislative measures and practical needs of researchers. Neither GDPR, nor Latvian legal framework regulate the particularities on the use of potentially identifiable health data in research. Also, the practical use of ‘public interest’ as a basis for lawful processing of personal data concerning health for research purposes is not clear. More extended involvement of research ethics committees might serve as useful tool for determination the ‘public interest’ and for the evaluation of proportionality when balancing the aims of the research and the personal data protection