This article concerns the legal regulation of medical research on children in Finland. The topic is covered by the Medical Research Act of 1999 and by the Recommendations issued by the Working group on medical research on children in 2003. The Decisions of the Parliamentary Ombudsman also play an important role in this area in Finland. The article focuses on two specific issues: involvement of guardians in decision-making for the child, and the expansion of the right to self-determination of minors. Two case examples on these topics are also discussed. Overall, the author comes to the conclusion that the Finnish legislation, policy-makers, investigators and the industry have succeeded well in taking into account international legislation in this area, although there is also room for improvement.