The Finnish Act on the Secondary Use of Social and Health Data (552/2019) entered into force on 1 May 2019. It applies to data collected in social and healthcare organisations and governs processing for secondary purposes, including statistics, scientific research, and other activities. The Act applies to personal data (as defined in the GDPR), but also governs other data, such as clinical data of deceased patients. This brief describes the Act especially as it applies to scientific research.